Any AnatomicalStructure which is not normally found in the Organism of which it is a part, i.e. it is the result of a PathologicProcess. This class covers tumors, birth marks, goiters, etc. Properties or qualities as distinguished from any particular embodiment of the properties/qualities in a physical medium. Instances of Abstract can be said to exist in the same sense as mathematical objects such as sets and relations, but they cannot exist at a particular place and time without some physical encoding or embodiment. One of the parts of speech. The Class of Words that conventionally denote Attributes of Objects. One of the parts of speech. The Class of Words that conventionally denote Attributes of Processes. A GroupOfPeople whose members all have the same age. Something or someone that can act on its own and produce changes in the world. Air is the gaseous stuff that makes up the atmosphere surrounding Earth. A Class containing all of the Attributes relating to the notions of possibility and necessity. A chiefly aquatic plant that contains chlorophyll, but does not form embryos during development and lacks vascular tissue. Any BodyMotion which is accomplished by means of the legs of an Animal for the purpose of moving from one point to another. A cold-blooded, smooth-skinned Vertebrate which characteristically hatches as an aquatic larva, breathing by gills. When mature, the Amphibian breathes with Lungs. A normal or pathological part of the anatomy or structural organization of an Organism. This class covers BodyParts, as well as structures that are given off by Organisms, e.g. ReproductiveBodies. The value of an angle in a plane or in a solid. A plane angle measure. Attributes that indicate whether an Organism is alive or not. An Organism with eukaryotic Cells, and lacking stiff cell walls, plastids, and photosynthetic pigments. AnatomicalStructures that are possessed exclusively by Animals. The subclass of Languages used by Animals other than Humans. BodySubstances that are produced exclusively by Animals. BinaryRelation ?REL is an AntisymmetricRelation if for distinct ?INST1 and ?INST2, (?REL ?INST1 ?INST2) implies not (?REL ?INST2 ?INST1). In other words, for all ?INST1 and ?INST2, (?REL ?INST1 ?INST2) and (?REL ?INST2 ?INST1) imply that ?INST1 and ?INST2 are identical. Note that it is possible for an AntisymmetricRelation to be a ReflexiveRelation. Various Primates with no tails or only short tails. The Class of all Months which are April. The Class of Mammals that dwell chiefly in the water. Includes whales, dolphins, manatees, seals, and walruses. A Class of Arthropods that includes ticks and spiders. Measures of the amount of space in two dimensions. Any proposition which has the form of a deductive or inductive argument, i.e. a set of premises which, it is claimed, imply a conclusion. Artifacts that are created primarily for aesthetic appreciation. Note that this Class does not include most examples of architecture, which belong under StationaryArtifact. A Class of Invertebrate that includes Arachnids and Insects. A relatively short Text that either is unbound or is bound with other Articles in a Book. A CorpuscularObject that is the product of a Making. The subclass of Languages that are designed by Humans. Asexual Processes of biological reproduction. A BinaryFunction is associative if bracketing has no effect on the value returned by the Function. More precisely, a Function ?FUNCTION is associative just in case (?FUNCTION ?INST1 (?FUNCTION ?INST2 ?INST3)) is equal to (?FUNCTION (?FUNCTION ?INST1 ?INST2) ?INST3), for all ?INST1, ?INST2, and ?INST3. The Class of all astronomical objects of significant size. It includes SelfConnectedObjects like planets, stars, and asteroids, as well as Collections like nebulae, galaxies, and constellations. Note that the planet Earth is an AstronomicalBody, but every Region of Earth is a GeographicArea. A BinaryRelation is asymmetric only if it is both an AntisymmetricRelation and an IrreflexiveRelation. An extremely small unit of matter that retains its identity in Chemical reactions. It consists of an AtomicNucleus and Electrons surrounding the AtomicNucleus. The core of the Atom. It is composed of Protons and Neutrons. A Process where one Object becomes attached to another Object. Note that this differs from Putting in that two things which are attached may already be in the same location. Note that Combining is different from Attaching in that the former applies to Substances, while the latter applies to CorpuscularObjects. Note too that Attaching is different from Putting in that one or both of the two things which are attached may or may not be moved from the location where they were combined. A Device whose purpose is to attach one thing to something else, e.g. nails, screws, buttons, etc. A Maneuver in a ViolentContest where the agent attempts to inflict damage on the patient. Qualities which we cannot or choose not to reify into subclasses of Object. The Class of all Months which are August. The class of PhysiologicProcesses of which there is not conscious awareness and control. A small, typically one-celled, prokaryotic Microorganism. A ViolentContest between two or more military units within the context of a war. Note that this does not cover the metaphorical sense of 'battle', which simply means a struggle of some sort. This sense should be represented with the more general concept of Contest. A GroupOfPeople whose members share a belief or set of beliefs. A FinancialTransaction where an instance of CurrencyMeasure is exchanged for the possibility of winning a larger instance of CurrencyMeasure within the context of some sort of Game. Any Food that is ingested by Drinking. Note that this class is disjoint with the other subclasses of Food, i.e. Meat and FruitOrVegetable. The Class of Functions that require two arguments. Elements from the number system with base 2. Every BinaryNumber is expressed as a sequence of the digits 1 and 0. A Predicate relating two items - its valence is two. BinaryRelations are relations that are true only of pairs of things. BinaryRelations are represented as slots in frame systems. Attributes that apply specifically to instances of Organism. A Process embodied in an Organism. A Substance that is capable of inducing a change in the structure or functioning of an Organism. This Class includes Substances used in the treatment, diagnosis, prevention or analysis of normal and abnormal body function. This Class also includes Substances that occur naturally in the body and are administered therapeutically. Finally, BiologicallyActiveSubstance includes Nutrients, most drugs of abuse, and agents that require special handling because of their toxicity. A Vertebrate having a constant body temperature and characterized by the presence of feathers. The Process of being born. One Bit of information. A one or a zero. A fluid present in Animals that transports Nutrients to and waste products away from various BodyParts. Any BodyPart which contains an unfilled space, e.g. BodyVessels, the atria and ventricles of the heart, the lungs, etc. Any BodyPart which is a covering of another BodyPart or of an entire Organism. This would include the rinds of FruitOrVegetables and the skins of Animals. The place where two BodyParts meet or connect. Any Motion where the agent is an Organism and the patient is a BodyPart. A collection of Cells and Tissues which are localized to a specific area of an Organism and which are not pathological. The instances of this Class range from gross structures to small components of complex Organs. The class of Attributes expressing configurations of bodies or parts of bodies of animals or humans, e.g. standing, sitting, kneeling, lying down, etc. Extracellular material and mixtures of cells and extracellular material that are produced, excreted or accreted by an Organism. Included here are Substances such as saliva, dental enamel, sweat, and gastric acid. Any tube-like structure which occurs naturally in an Organism and through which a BodySubstance can circulate. The Class of Processes where an Object is heated and converted from a Liquid to a Gas. Rigid Tissue composed largely of calcium that makes up the skeleton of Vertebrates. Note that this Class also includes teeth. A Text that has pages and is bound. The subclass of Getting Processes where the agent gets something for a limited period of time with the expectation that it will be returned later (perhaps with interest). The Process of respiration, by which oxygen is made available to an Animal. This covers processes of inhalation, exhalation, and alternations between the two. An energy measure. The Class of StationaryArtifacts which are intended to house Humans and their activities. A FinancialTransaction in which an instance of CurrencyMeasure is exchanged for an instance of Physical. One Byte of information. A Byte is eight Bits. IntentionalPsychologicalProcesses which involve the consideration and/or manipulation of instances of Quantity. A Calorie is an energy measure. The Class of Carnivores with completely separable toes, nonretractable claws, and long muzzles. An element of living cells and a source of energy for Animals. This class includes both simple Carbohydrates, i.e. sugars, and complex Carbohydrates, i.e. starches. The Class of flesh-eating Mammals. Members of this Class typically have four or five claws on each paw. Includes cats, dogs, bears, racoons, and skunks. Transfer from one point to another by means of an Animal or Human. The Class of Predicates relating the spatially distinguished parts of a Process. CaseRoles include, for example, the agent, patient or destination of an action, the flammable substance in a burning process, or the water that falls in rain. The fundamental structural and functional unit of living Organisms. A TemperatureMeasure. The freezing point and the boiling point of water are, respectively, 0 CelsiusDegrees and 100 CelsiusDegrees. Submultiple of Meter. Symbol: cm. It is the 100th part of a Meter A Text that confers a right or obligation on the holder of the Certificate. Note that the right or obligation need not be a legal one, as in the case of an academic diploma that grants certain privileges in the professional world. The Class of Processes where ownership of something is transferred from one Agent to another. An element of an alphabet, a set of numerals, etc. Note that a Character may or may not be part of a Language. Character is a subclass of SymbolicString, because every instance of Character is an alphanumeric sequence consisting of a single element. The Class of ChemicalProcesses in which a CompoundSubstance breaks down into simpler products. A ChemicalProcess occurs whenever chemical compounds (CompoundSubstances) are formed or decomposed. For example, reactants disappear as chemical change occurs, and products appear as chemical change occurs. In a chemical change a chemical reaction takes place. Catalysts in a ChemicalProcess may speed up the reaction, but aren't themselves produced or consumed. Examples: rusting of iron and the decomposition of water, induced by an electric current, to gaseous hydrogen and gaseous oxygen. The Class of ChemicalProcesses in which a CompoundSubstance is formed from simpler reactants. A LandArea of relatively small size, inhabited by a community of people, and having some sort of political structure. Note that this class includes both large cities and small settlements like towns, villages, hamlets, etc. Classes differ from Sets in three important respects. First, Classes are not assumed to be extensional. That is, distinct Classes might well have exactly the same instances. Second, Classes typically have an associated `condition' that determines the instances of the Class. So, for example, the condition `human' determines the Class of Humans. Note that some Classes might satisfy their own condition (e.g., the Class of Abstract things is Abstract) and hence be instances of themselves. Third, the instances of a class may occur only once within the class, i.e. a class cannot contain duplicate instances. The Class of IntentionalPsychologicalProcesses which involve attaching a name or category to a thing or set of things. Note that Classifying is distinguished from Learning by the fact that the latter covers the acquisition by a CognitiveAgent of any Proposition, while the former involves the assignment of a label or category. Any TwoDimensionalFigure which has a well defined interior and exterior. Artifact made out of fabrics and possibly other materials that are used to cover the bodies of Humans. Any GasMixture that is visible, e.g. Smoke produced by a fire or clouds of water vapor in the sky. A SentientAgent with responsibilities and the ability to reason, deliberate, make plans, etc. This is essentially the legal/ethical notion of a person. Note that, although Human is a subclass of CognitiveAgent, there may be instances of CognitiveAgent which are not also instances of Human. For example, chimpanzees, gorillas, dolphins, whales, and some extraterrestrials (if they exist) may be CognitiveAgents. Vertebrates whose body temperature is not internally regulated. Collections have members like Classes, but, unlike Classes, they have a position in space-time and members can be added and subtracted without thereby changing the identity of the Collection. Some examples are toolkits, football teams, and flocks of sheep. The Class of Attributes relating to the color of Objects. The subclass of SurfaceChange where a ColorAttribute of the patient is altered. A Process where two or more SelfConnectedObjects are incorporated into a single SelfConnectedObject. Note that Combining is different from Attaching in that the former results in one of the objects being part of the other, while Attaching only results in the two objects being connected with one another. Note too that Combining is different from Putting in that one or both of the two things which are combined may or may not be moved from the location where they were combined. The Class of ChemicalProcesses in which an Object reacts with oxygen and gives off heat. This includes all Processes in which something is burning. An Agent that provides products and/or services for a fee with the aim of making a profit. Any FinancialTransaction by a CommercialAgent where the aim is to produce a profit. Instances of this Class commit the agent to some future course. For example, Bob promised Susan that he would be home by 11pm. A SocialInteraction that involves the transfer of information between two or more CognitiveAgents. Note that Communication is closely related to, but essentially different from, ContentDevelopment. The latter involves the creation or modification of a ContentBearingObject, while Communication is the transfer of information for the purpose of conveying a message. A BinaryFunction is commutative if the ordering of the arguments of the function has no effect on the value returned by the function. More precisely, a function ?FUNCTION is commutative just in case (?FUNCTION ?INST1 ?INST2) is equal to (?FUNCTION ?INST2 ?INST1), for all ?INST1 and ?INST2. The Class of IntentionalPsychologicalProcesses which involve comparing, relating, contrasting, etc. the properties of two or more Entities. A Number that has the form: x + yi, where x and y are RealNumbers and i is the square root of -1. The Class of Substances that contain two or more elements (ElementalSubstances), in definite proportion by weight. The composition of a pure compound will be invariant, regardless of the method of preparation. Compounds are composed of more than one kind of atom (element). The term molecule is often used for the smallest unit of a compound that still retains all of the properties of the compound. Examples: Table salt (sodium chloride, NaCl), sugar (sucrose, C_{12}H_{22}O_{11}), and water (H_2O). The class of Languages designed for and interpreted by a computer. A set of instructions in a computer programming language that can be executed by a computer. The Class of Processes where an Object is cooled and converted from a Gas to a Liquid. The Class of Keeping Processes where the patient is a Human or an Animal and is kept involuntarily. This covers caging, imprisonment, jailing, etc. Attributes that indicate whether an Organism is conscious or the qualitative degree of consciousness of an Organism. A ConstantQuantity is a PhysicalQuantity which has a constant value, e.g. 3 meters and 5 hours. The magnitude (see MagnitudeFn) of every ConstantQuantity is a RealNumber. ConstantQuantities are distinguished from FunctionQuantities, which map ConstantQuantities to other ConstantQuantities. All ConstantQuantites are expressed with the BinaryFunction MeasureFn, which takes a Number and a UnitOfMeasure as arguments. For example, 3 Meters can be expressed as (MeasureFn 3 Meter). ConstantQuantities form a partial order (see PartialOrderingRelation) with the lessThan relation, since lessThan is a RelationExtendedToQuantities and lessThan is defined over the RealNumbers. The lessThan relation is not a total order (see TotalOrderingRelation) over the class ConstantQuantity since elements of some subclasses of ConstantQuantity (such as length quantities) are incomparable to elements of other subclasses of ConstantQuantity (such as mass quantities). An ConstructedLanguage is a HumanLanguage that did not evolve spontaneously within a language community, but rather had its core grammar and vocabulary invented by one or more language experts, often with an aim to produce a more grammatically regular language than any language that has evolved naturally. This Class includes languages like Esperanto that were created to facilitate international communication The subclass of Making in which a StationaryArtifact is built. Any SelfConnectedObject that expresses content. This content may be a Proposition, e.g. when the ContentBearingObject is a Sentence or Text, or it may be a representation of an abstract or physical object, as with an Icon, a Word or a Phrase. A subclass of IntentionalProcess in which content is modified, its form is altered or it is created anew. A SocialInteraction where the agent and patient are CognitiveAgents who are trying to defeat one another. Note that this concept is often applied in a metaphorical sense in natural language, when we speak, e.g., of the struggle of plants for space or sunlight, or of bacteria for food resources in some environment. A Class containing Attributes that are specific to participants in a Contest. In particular, these Attributes indicate the position of one of the agents in the Contest with respect to other agent(s) in the Contest. Some examples of these Attributes are winning, losing, won, lost, etc. One of the seven largest land masses on earth, viz. Africa, North America, South America, Antarctica, Europe, Asia, and Oceania. Note that this naming scheme is the one used in the CIA World Factbook. Functions which are continuous. This concept is taken as primitive until representations for limits are devised. The Making of an instance of Food. Note that this can cover any preparation of Food, e.g. making a salad, cutting up fruit, etc. It does not necessarily involve the application of heat. Any Decreasing Process where the PhysicalQuantity decreased is a TemperatureMeasure. The subclass of SocialInteraction where the participants involved work together for the achievement of a common goal. An Organization that has a special legal status that allows a group of persons to act as a CommercialAgent and that insulates the owners (shareholders) from many liabilities that might result from the corporation's operation. A SelfConnectedObject whose parts have properties that are not shared by the whole. Enumerating something. The Class of Calculating Processes where the aim is to determine the Number corresponding to the patient. The Class of Putting processes where the agent covers the patient, either completely or only partially, with something else. The subclass of Process in which something is created. Note that the thing created is specified with the result CaseRole. A Class of Arthropods that mainly dwells in water and has a segmented body and a chitinous exoskeleton. Includes lobsters, crabs, shrimp, and barnacles. English unit of volume equal to 1/2 of a Pint. Any element of the official currrency of some Nation. This covers both CurrencyBills and CurrencyCoins. Any instance of Currency that is made of paper. Any instance of Currency that is made of Metal. Includes all standard measures of monetary value, including UnitedStatesDollar, UnitedStatesCent, Lire, Yen, etc. The subclass of Poking Processes which involve a sharp instrument. The Class of Processes where the agent brings about a situation where the patient no longer functions normally or as intended. The Class of all calendar Days. Time unit. 1 day = 24 hours. The Process of dying. The Class of all Months which are December. The subclass of Selecting where the agent opts for one course of action out of a set of multiple possibilities that are open to him/her. The Class of LinguisticCommunications that effect an institutional alteration when performed by competent authority. Some examples are nominating, marrying, and excommunicating. Converting a document or message that has previously been encoded (see Encoding) into a Language that can be understood by a relatively large number of speakers. Any QuantityChange where the PhysicalQuantity is decreased. An Argument which has the form of a deduction, i.e. it is claimed that the set of premises entails the conclusion. A Maneuver in a ViolentContest where the agent attempts to avoid being damaged. Exhibiting something or a range of things before the public in a particular location. This would cover software demos, theatrical plays, lectures, dance and music recitals, museum exhibitions, etc. A Class containing all of the Attributes relating to the notions of permission, obligation, and prohibition. The spatial analogue of Planning. Designing a Collection of Objects involves determining a placement of the Objects with respect to one another and perhaps other Objects as well, in order to satisfy a particular purpose. The subclass of Damagings in which the patient (or an essential element of the patient) is destroyed. Note that the difference between this concept and its superclass is solely one of extent. A Process where the agent detaches one thing from something else. Note that Detaching is different from Separating in that the latter applies to Substances, while the former applies to CorpuscularObjects. Note too that Detaching is different from Removing in that one or both of the two things which are detached may or may not be moved from the location where they were attached. Attributes that indicate the stage of development of an Organism. A Device is an Artifact whose purpose is to serve as an instrument in a specific subclass of Process. A Process that is carried out for the purpose of determining the nature of a DiseaseOrSyndrome. The Process by which Food that has been ingested is broken down into simpler chemical compounds and absorbed by the Organism. Instances of this Class urge some further action among the receivers. A Directing can be an Ordering, a Requesting or a Questioning. The act of changing the direction in which the patient of the act is oriented. The subclass of PositionalAttributes that concern compass directions. Finding something that was sought. Note that this class is restricted to cases of discovering something Physical. For cases involving the acquisition of knowledge, the class Learning should be used. A BiologicalAttribute which qualifies something that alters or interferes with a normal process, state or activity of an Organism. It is usually characterized by the abnormal functioning of one or more of the host's systems, parts, or Organs. Any Communication that involves a single agent and many destinations. This covers the release of a published book, broadcasting, a theatrical performance, giving orders to assembled troops, delivering a public lecture, etc. The Process by which liquid Food, i.e. Beverages, are incorporated into an Animal. Controlling the direction and/or speed of a Vehicle. This includes navigating a ship, driving a car or truck, operating a train, etc. The Class of Processes where a Liquid is removed from an Object. Any Process that requires two, nonidentical patients. The Process by which solid Food is incorporated into an Animal. A EducationalOrganization is an institution of learning. Some examples are public and private K-12 schools, and colleges and universities. Any Process which is intended to result in Learning. The fertilized or unfertilized female ReproductiveBody of an Animal. This includes Bird and Reptile eggs, as well as mammalian ova. Election is the class of events conducted by an organization, in which qualified participants vote for officers, adopt resolutions, or settle other issues in that Organization. SubatomicParticles that surround the AtomicNucleus. They have a negative charge. The Class of PureSubstances that cannot be separated into two or more Substances by ordinary chemical (or physical) means. This excludes nuclear reactions. ElementalSubstances are composed of only one kind of atom. Examples: Iron (Fe), copper (Cu), and oxygen (O_2). ElementalSubstances are the simplest PureSubstances. The Class of Attributes that denote emotional states of Organisms. Converting a document or message into a formal language or into a code that can be understood only by a relatively small body of Agents. Generally speaking, this hinders wide dissemination of the content in the original document or message. A fundamental concept that applies in many engineering domains. An EngineeringComponent is an element of a Device that is a physically whole object, such as one might see listed as standard parts in a catalog. The main difference betweeen EngineeringComponents and arbitrary globs of matter is that EngineeringComponents are object-like in a modeling sense. Thus, an EngineeringComponent is not an arbtrary subregion, but a part of a system with a stable identity. An EngineeringConnection is an EngineeringComponent that represents a connection relationship between two other EngineeringComponents. It is a reification of the Predicate connectedEngineeringComponents. That means that whenever this Predicate holds between two EngineeringComponents, there exists an EngineeringConnection. The practical reason for reifying a relationship is to be able to attach other information about it. For example, one might want to say that a particular connection is associated with some shared parameters, or that it is of a particular type. EngineeringConnections are EngineeringComponents and can therefore be an engineeringSubcomponent of other EngineeringComponents. However, to provide for modular regularity in component systems, EngineeringConnections cannot be connected. For each pair of EngineeringComponents related by connectedEngineeringComponents, there exists at least one EngineeringConnection. However, that object may not be unique, and the same EngineeringConnection may be associated with several pairs of EngineeringComponents. The universal class of individuals. This is the root node of the ontology. A BinaryRelation is an equivalence relation if it is a ReflexiveRelation, a SymmetricRelation, and a TransitiveRelation. A GroupOfPeople whose members originate from the same GeographicArea or share the same Language and/or cultural practices. A currency measure. 1 EuroCent is equal to .01 EuroDollars. A currency measure of most European Union countries. It is based on the UnitedStatesDollar. An Integer that is evenly divisible by 2. Investigating the truth of a Proposition by constructing and observing a trial. Note that the trial may be either controlled or uncontrolled, blind or not blind. An Argument where the conclusion is an observed fact and the premises are other facts which collectively imply the conclusion. Note that this is the they hypothetico-deductive model of explanation. Instances of this Class express a state of the agent. For example, Jane thanked Barbara for the present she had given her. The thanking in this case expresses the gratitude of Jane towards Barbara. Note that Expressing, unlike the other speech act types, is not a subclass of LinguisticCommunication. This is because emotions, for example, can be expressed without language, e.g. by smiling. Artifacts that are created by weaving together natural or synthetic fibers or by treating the skins of certain sorts of Animals. Note that this Class includes articles that are created by stitching together various types of fabrics, e.g. bedspreads. On the other hand, Clothing is not a subclass of Fabric, because many clothing items contain elements that are not fabrics. The class of Texts that purport to reveal facts about the world. Such texts are often known as information or as non-fiction. Note that something can be an instance of FactualText, even if it is wholly inaccurate. Whether something is a FactualText is determined by the beliefs of the agent creating the text. A TemperatureMeasure that is commonly used in the United States. On the Fahrenheit scale, the freezing point of water is 32 FahrenheitDegrees, and the boiling point of water is 212 FahrenheitDegrees. A GroupOfPeople whose members bear familyRelations to one another. Nonrigid Tissue that is composed largely of fat cells. The Class of all Months which are February. The Class of Carnivores with completely separable toes, nonretractable claws, slim bodies, and rounded heads. A NonFloweringPlant that contains vascular tissue. This class includes true ferns, as well as horsetails, club mosses, and whisk ferns. The class of Texts that purport to be largely a product of the author's imagination, i.e. the author does not believe that most of the content conveyed by the text is an accurate depiction of the real world. Note that something can be an instance of FictionalText, even if it is completely true. Whether something is a FictionalText is determined by the beliefs of the agent creating the text. An academic or applied discipline with recognized experts and with a core of accepted theory or practice. Note that FieldOfStudy is a subclass of Proposition, because a FieldOfStudy is understood to be a body of abstract, informational content, with varying degrees of certainty attached to each element of this content. A document having monetary value or recording a monetary transaction A Transaction where an instance of Currency is exchanged for something else. A Set containing a finite number of elements. A cold-blooded aquatic Vertebrate characterized by fins and breathing by gills. Included here are Fish having either a bony skeleton, such as a perch, or a cartilaginous skeleton, such as a shark. Also included are those Fish lacking a jaw, such as a lamprey or hagfish. A Plant that produces seeds and flowers. This class includes trees, shrubs, herbs, and flowers. Any SelfConnectedObject containing Nutrients, such as carbohydrates, proteins, and fats, that can be ingested by a living Animal and metabolized into energy and body tissue. English length unit of feet. A syntactically well-formed formula in the SUO-KIF knowledge representation language. The Class of Processes where an Object is cooled and converted from a Liquid to a Solid. A WaterArea whose Water is not saline, e.g. most rivers and lakes. The Class of all calendar Fridays. Any fruit or vegetable, i.e. a ripened ReproductiveBody of a Plant. Note that FruitOrVegetable is not a subclass of Food, because some fruits, e.g. poisonous berries, are not edible. A Function is a term-forming Relation that maps from a n-tuple of arguments to a range and that associates this n-tuple with at most one range element. Note that the range is a SetOrClass, and each element of the range is an instance of the SetOrClass. A FunctionQuantity is a PhysicalQuantity that is returned by a Function that maps from one or more instances of ConstantQuantity to another instance of ConstantQuantity. For example, the velocity of a particle would be represented by a FunctionQuantity relating values of time (which are ConstantQuantities) to values of distance (also ConstantQuantities). Note that all elements of the range of the Function corresponding to a FunctionQuantity have the same physical dimension as the FunctionQuantity itself. Any instance of Giving where the patient is an instance of Currency. Note that this class covers both financing, e.g. where a firm funds a software company with venture capital with the agreement that a certain percentage of the profits on the investment will be returned to the firm, and instances of UnilateralGiving, e.g. providing a tuition waiver and/or a stipend to a student as part of scholarship or fellowship. A eukaryotic Organism characterized by the absence of chlorophyll and the presence of rigid cell walls. Included here are both slime molds and true fungi such as yeasts, molds, mildews, and mushrooms. A Contest whose purpose is the enjoyment/stimulation of the participants or spectators of the Game. Any Mixture that satisfies two conditions, viz. it is made up predominantly of things which are a Gas and any component other than Gas in the Mixture is in the form of fine particles which are suspended in the Gas. Any Motion where the patient is a Gas. This class would cover, in particular, the motion of Air, e.g. a breeze or wind. A geographic location, generally having definite boundaries. Note that this differs from its immediate superclass Region in that a GeographicArea is a three-dimensional Region of the earth. Accordingly, all astronomical objects other than earth and all one-dimensional and two-dimensional Regions are not classed under GeographicArea. The class of activities that are caused by geological forces and affect geological features, and which may affect the biosphere as well. The class of all geometric figures, i.e. the class of all abstract, spatial representations. The instances of this class are GeometricPoints, TwoDimensionalFigures or ThreeDimensionalFigures. The class of zero-dimensional GeometricFigures, i.e. the class of GeometricFigures that have position but lack extension in any dimension. Any GeographicArea which is associated with some sort of political structure. This class includes Lands, Cities, districts of cities, counties, etc. Note that the identity of a GeopoliticalArea may remain constant after a change in borders. Any BodyMotion, e.g. a hand wave, a nod of the head, a smile, which is also an instance of Communication. The subclass of ChangeOfPossession where the agent gets something. Note that the source from which something is obtained is specified with the origin CaseRole. The subclass of ChangeOfPossession where the agent gives the destination something. Any instance of Giving where the agent gives something to the destination which was previously given to the agent by the destination, e.g. returing a book that was borrowed from someone. The ruling body of a GeopoliticalArea. GovernmentOrganization is the class of official Organizations that are concerned with the government of a GeopoliticalArea at some level. They may be a subOrganization of a government. Any instance of Touching which results in a situation where the agent grasps the patient of the Touching. The OrganizationalProcess of graduating from an EducationalOrganization. Submultiple of kilogram. Symbol: g. 1 kilogram = 1000 Grams. A Collection of Agents, e.g. a flock of sheep, a herd of goats, or the local Boy Scout troop. Any Group whose members are exclusively Humans. The Process of biological development in which an Organism or part of an Organism changes its form or its size. Any IntentionalProcess where the agent tries to direct the behavior of another Object, whether an Agent or not. The subclass of Perception in which the sensing is done by an auditory Organ. Any Increasing Process where the PhysicalQuantity increased is a TemperatureMeasure. SI frequency measure. Symbol: Hz. It is the number of cycles per second. Hertz = s^(-1). Note that Hertz does not have a conversion function. OrganizationalProcesses where someone is made an employee of an Organization. A hole is an immaterial body located at the surface of an Object. Since every Hole is ontologically dependent on its host (i.e., the object in which it is a hole), being a Hole is defined as being a hole in something. Note that two Holes may occupy the same region, or part of the same region, without sharing any parts. Includes Humans and relatively recent ancestors of Humans. The Class of quadruped Mammals with hooves. Includes horses, cows, sheep, pigs, antelope, etc. A ResidentialBuilding which provides temporary accommodations to guests in exchange for money. The Class of all clock Hours. Time unit. 1 hour = 60 minutes. Modern man, the only remaining species of the Homo genus. The subclass of Languages used by Humans. This is the subclass of ContentBearingObjects which are not part of a Language and which have some sort of similarity with the Objects that they represent. This Class would include symbolic roadway signs, representational art works, photographs, etc. Any Number that is the result of multiplying a RealNumber by the square root of -1. Any Touching where something comes into sudden, forceful, physical contact with something else. Some examples would be striking, knocking, whipping etc. The subclass of Transfer where the patient travels through space by means of a sudden, forceful event. Some examples would be shooting, throwing, tossing, etc. English length unit of inches. Any QuantityChange where the PhysicalQuantity is increased. An Argument which is inductive, i.e. it is claimed that a set of specific cases makes the conclusion, which generalizes these cases, more likely to be true. Measures of the amount of information. Includes Bit, Byte, and multiples of these, e.g. KiloByte and MegaByte. The Process by which Food is taken into an Animal. This is a Class of Classes. Each instance of InheritableRelation is a subclass of Relation whose properties can be inherited downward in the class hierarchy via the subrelation Predicate. Inserting a BiologicallyActiveSubstance into an Animal or a Human with a syringe. The process of creating a traumatic wound or injury. Since Injuring is not possible without some biologic function of the organism being injured, it is a subclass of BiologicalProcess. A Class of small Arthropods that are air-breathing and that are distinguished by appearance. Putting one thing inside of another thing. A negative or nonnegative whole number. A Process that has a specific purpose for the CognitiveAgent who performs it. An IntentionalProcess that can be realized entirely within the mind or brain of an Organism. Thus, for example, Reasoning is a subclass of IntentionalPsychologicalProcess, because one can reason simply by exercising one's mind/brain. On the other hand, RecreationOrExercise is not a subclass of IntentionalPsychologicalProcess, because many instances of RecreationOrExercise necessarily have subProcesses of BodyMotion. The Class of Relations between an Agent and one or more Entities, where the Relation requires that the Agent have awareness of the Entity. Any Attribute of an Entity that is an internal property of the Entity, e.g. its shape, its color, its fragility, etc. Processes which involve altering an internal property of an Object, e.g. the shape of the Object, its coloring, its structure, etc. Processes that are not instances of this class include changes that only affect the relationship to other objects, e.g. changes in spatial or temporal location. Any Process of assigning a Proposition to a Text, i.e. understanding the Text. A BinaryRelation ?REL is intransitive only if (?REL ?INST1 ?INST2) and (?REL ?INST2 ?INST3) imply not (?REL ?INST1 ?INST3), for all ?INST1, ?INST2, and ?INST3. DeductiveArguments that are not ValidDeductiveArguments, i.e. it is not the case that the set of premises in fact entails the conclusion. An Animal which has no spinal column. The class of IntentionalPsychologicalProcesses where the agent attempts to obtaina information (i.e. a Proposition denoted by a Formula). Any RealNumber that is not also a RationalNumber. Relation ?REL is irreflexive if (?REL ?INST ?INST) holds for no value of ?INST. A LandArea that is completely surrounded by a WaterArea. The Class of all Months which are January. The OrganizationalProcess of becoming a member of an Organization. The subclass of Selecting where the agent opts for one belief out of a set of multiple possibilities that are available to him/her. JudicialOrganization is the class of Organizations whose primary purpose is to render judgments according to the statutes or regulations of a government or other organization. Judicial bodies are not necessarily government organizations, for example, those associated with sporting associations. Any legal proceeding which is conducted by a JudicialOrganization. Note that there is an important difference between the concepts LegalAction and JudicialProcess. The former refers to legal claims that are brought by a plaintiff, e.g. law suits, while the second refers to trials and other sorts of judicial hearings where the merits of a LegalAction are decided. The Class of all Months which are July. The Class of all Months which are June. The Class of Processes where the agent keeps something in a particular location for an extended period of time. SI TemperatureMeasure. Symbol: K. It is one of the base units in SI (it is also a unit in the ITS system). Kelvin differs from the Celsius scale in that the triple point of water is defined to be 273.16 KelvinDegrees while it is 0 CelsiusDegrees. The magnitudes of intervals in the two scales are the same. By definition the conversion constant is 273.15. The subclass of Destruction in which the death of an Organism is caused by an Organism. Note that in cases of suicide the Organism would be the same in both cases. One KiloByte (KB) of information. One KiloByte is 1024 Bytes. Note that this sense of 'kilo' is different from the one accepted in the SI system. An area which is predominantly solid ground, e.g. a Nation, a mountain, a desert, etc. Note that a LandArea may contain some relatively small WaterAreas. For example, Australia is a LandArea even though it contains various rivers and lakes. LandTransitway is the subclass of Transitway that represents areas intended for motion over the ground. A system of signs for expressing thought. The system can be either natural or artificial, i.e. something that emerges gradually as a cultural artifact or something that is intentionally created by a person or group of people. The Class of all leap years. These are years which are either (i.) evenly divisible by 4 and not by 100 or (ii.) evenly divisible by 400 (this latter case is known as a leap century). The Class of Processes which relate to the acquisition of information. The OrganizationalProcess of leaving an Organization, whether voluntarily or involuntarily. Any Process where a CognitiveAgent seeks to obtain something through a court of law. A decision issued by a court with respect to a LegalAction. Note that a LegalDecision is the act of Declaring a decision of a court; it is not the act of judge or jury Deciding the merits of a particular LegalAction. The subclass of Giving Processes where the agent gives the destination something for a limited period of time with the expectation that it will be returned later (perhaps with interest). The Class of ConstantQuantities relating to length. A Communication that involves the transfer of information via a LinguisticExpression. This is the subclass of ContentBearingObjects which are language-related. Note that this Class encompasses both Language and the the elements of Languages, e.g. Words. Any Mixture that satisfies two conditions, viz. it is made up predominantly of things which are a Liquid and any component other than Liquid in the Mixture is in the form of fine particles which are suspended in the Liquid. Any Motion where the patient is a Liquid. This class would cover, in particular, the flow of Water. Every List is a particular ordered n-tuple of items. Generally speaking, Lists are created by means of the ListFn Function, which takes any number of items as arguments and returns a List with the items in the same order. Anything, including other Lists, may be an item in a List. Note too that Lists are extensional - two lists that have the same items in the same order are identical. Note too that a List may contain no items. In that case, the List is the NullList. Any instance of Hearing which is intentional. Unit of volume in the metric system. It is currently defined to be equal to one cubic decimeter (0.001 cubic meter). Symbol: l. Any instance of Seeing which is intentional. Machines are Devices that that have a well-defined resource and result and that automatically convert the resource into the result. The Class of Processes where the agent cares for or maintains the Object. The subclass of Creation in which an individual Artifact or a type of Artifact is made. A Vertebrate having a constant body temperature and characterized by the presence of hair, mammary glands, and sweat glands. The class of Male Humans. OrganizationalProcesses that involve overseeing the activities of others. Note the key differences between RegulatoryProcess and its sibling Managing. The latter implies a long-term relationship between the manager and the managed, while the former implies a normative standard to which the activities of the regulated are referred. An intentional move or play within a Contest. In many cases, a Maneuver is a realization of part of a strategy for winning the Contest, but it also may be just an arbitrary or semi-arbitrary division of the overarching Contest, e.g. innings in a baseball game. A ManualHumanLanguage is a HumanLanguage which has as its medium gestures and movement, such as the shape, position, and movement of the hands. The Making of Artifacts on a mass scale. Any Corporation which manufactures Products. The Class of all Months which are March. The Class of Mammals which have a pouch for their young. The Class of ConstantQuantities relating to the amount of matter in an Object. The OrganizationalProcess of joining an EducationalOrganization as a student. The Class of all Months which are May. The Class of Calculating Processes where the aim is to determine the PhysicalQuantity of some aspect of the patient. Any Device whose purpose is to measure a PhysicalQuantity. Any Food which was originally part of an Animal and is not ingested by drinking, including eggs and animal blood that is eaten as food. Note that this class covers both raw meat and meat that has been prepared in some way, e.g. by cooking. Note too that preparations involving Meat and FruitOrVegetable are classed directly under Food. The coming together of two or more CognitiveAgents for the purpose of Communication. This covers informal meetings, e.g. visits with family members, and formal meetings, e.g. a board of directors meeting. One MegaByte (MB) of information. One MegaByte is 1024 KiloBytes. Note that this sense of 'mega' is different from the one accepted in the SI system. The Class of Processes where an Object is heated and converted from a Solid to a Liquid. Any Corporation which sells goods or services to customers for a profit. A Metal is an ElementalSubstance that conducts heat and electricity, is shiny and reflects many colors of light, and can be hammered into sheets or drawn into wire. About 80% of the known chemical elements (ElementalSubstances) are metals. SI LengthMeasure. Symbol: m. It is one of the base units in SI, and it is currently defined as follows: the Meter is the length of the path traveled by light in a vacuum during a time interval of 1/299792458 of a SecondDuration. An Organism that can be seen only with the aid of a microscope. English length unit of miles. MilitaryForce is the subclass of Organizations that are organized along military lines and for the purpose of either defensive or offensive combat, whether or not the force is an official GovernmentOrganization. Any heavily armed Organization that is part of a Government and that is charged with representing the Government in international conflicts. Any Process that is carried out by a military organization. Note that this class covers Processes, e.g. military operations, that are the result of careful planning, as well as those which are unscripted. Any of various naturally occurring homogeneous substances (such as stone, coal, salt, sulfur, sand, petroleum), or synthetic substances having the chemical composition and crystalline form and properties of a naturally occurring mineral. The Class of all clock Minutes. Time unit. 1 minute = 60 seconds. A Mixture is two or more PureSubstances, combined in varying proportions - each retaining its own specific properties. The components of a Mixture can be separated by physical means, i.e. without the making and breaking of chemical bonds. Examples: Air, table salt thoroughly dissolved in water, milk, wood, and concrete. A molecule is the smallest unit of matter of a CompoundSubstance that retains all the physical and chemical properties of that substance, e.g., Ne, H2, H2O. A molecule is two or more Atoms linked by a chemical bond. Soft-bodied Invertebrate that is usually contained in a shell. Includes oysters, clams, mussels, snails, slugs, octopi, and squid. The Class of all calendar Mondays. Various Primates with relatively long tails. The Class of all calendar Months. Part of a Word which cannot be subdivided and which expresses a meaning. A NonFloweringPlant without true roots and little if any vascular tissue. Any Process of movement. Nonrigid Tissue appearing only in Animals and composed largely of contractile cells. The subclass of RadiatingSound where the sound is intended to be melodic and is produced deliberately. A Device which is manipulated by a Human and whose purpose is to produce Music. A SetOrClass is a MutuallyDisjointClass just in case there exists nothing which is an instance of all of the instances of the original SetOrClass. A Class of Arthropods that includes centipedes and millipedes. The Process of assigning a name to someone or something. The broadest GeopoliticalArea, i.e. Nations are GeopoliticalAreas that are not part of any other overarching and comprehensive governance structure (excepting commonwealths and other sorts of loose international organizations). The subclass of HumanLanguages which are not designed and which evolve from generation to generation. This Class includes all of the national languages, e.g. English, Spanish, Japanese, etc. Note that this class includes dialects of natural languages. Any Substance that is not the result of an IntentionalProcess, i.e. any substance that occurs naturally. An Integer that is less than zero. A RealNumber that is less than zero. Components of the AtomicNucleus. They have no charge. A Plant that reproduces with spores and does not produce flowers. Any SetOrClass that contains at least one instance. An Integer that is greater than or equal to zero. A RealNumber that is greater than or equal to zero. A Class containing all of the Attributes that are specific to morality, legality, aesthetics, etiquette, etc. Many of these attributes express a judgement that something ought or ought not to be the case. One of the parts of speech. The Class of Words that conventionally denote Objects. A Phrase that has the same function as a Noun. The Class of all Months which are November. Any SetOrClass that contains no instances. A measure of how many things there are, or how much there is, of a certain kind. Numbers are subclassed into RealNumber, ComplexNumber, and ImaginaryNumber. A BiologicallyActiveSubstance required by an Organism. It is generally ingested as Food, and it is of primary interest because of its role in the biologic functioning of the Organism. Corresponds roughly to the class of ordinary objects. Examples include normal physical objects, geographical regions, and locations of Processes, the complement of Objects in the Physical class. In a 4D ontology, an Object is something whose spatiotemporal extent is thought of as dividing into spatial parts roughly parallel to the time-axis. The Class of IntentionalRelations where the Agent has awareness of an instance of Physical. The Class of NormativeAttributes that are associated with an objective criterion for their attribution, i.e. there is broad consensus about the cases where these attributes are applicable. The Class of all Months which are October. An Integer that is not evenly divisible by 2. The subclass of Committing in which a CognitiveAgent offers something Physical to another agent. Offerings may be unconditional (in which case they are a promise to effect a UnilateralGiving) or conditional (in which case they are a promise to effect a Transaction of some sort). The class of GeometricFigures that have position and an extension along a single dimension, viz. straight lines. The Class of UnaryFunctions which are one to one. A function F is one to one just in case for all X, Y in the domain of F, if X is not identical to Y, then F(X) is not identical to F(Y). The class of TwoDimensionalFigures that are not ClosedTwoDimensionalFigures. A Directing in which the receiver is commanded to realize the content of a ContentBearingObject. Orders are injunctions, the disobedience of which involves sanctions, or which express an obligation upon the part of the orderee. A somewhat independent BodyPart that performs a specialized function. Note that this functional definition covers bodily systems, e.g. the digestive system or the central nervous system. A PhysiologicProcess of a particular Organ or Tissue. This class encompasses Organisms, CorpuscularObjects that are parts of Organisms, i.e. BodyParts, and CorpuscularObjects that are nonintentionally produced by Organisms, e.g. ReproductiveBodies. Generally, a living individual, including all Plants and Animals. A physiologic function of the Organism as a whole, of multiple organ systems or of multiple Organs or Tissues. An Organization is a corporate or similar institution. The members of an Organization typically have a common purpose or function. Note that this class also covers divisions, departments, etc. of organizations. For example, both the Shell Corporation and the accounting department at Shell would both be instances of Organization. Note too that the existence of an Organization is dependent on the existence of at least one member (since Organization is a subclass of Collection). Accordingly, in cases of purely legal organizations, a fictitious member should be assumed. An IntentionalProcess that involves an Organization. English unit of volume equal to 1/8 of a Cup. A SetOrClass is a PairwiseDisjointClass just in case every instance of the SetOrClass is either equal to or disjoint from every other instance of the SetOrClass. An Organization which is much like a MilitaryOrganization, e.g. it is made up of armed fighters, except that it is not associated with a Government. A BinaryRelation is a partial ordering if it is a ReflexiveRelation, an AntisymmetricRelation, and a TransitiveRelation. A Relation is a PartialValuedRelation just in case it is not a TotalValuedRelation, i.e. just in case assigning values to every argument position except the last one does not necessarily mean that there is a value assignment for the last argument position. Note that, if a Relation is both a PartialValuedRelation and a SingleValuedRelation, then it is a partial function. An umbrella Class for any Word that does not fit into the other subclasses of Word. A ParticleWord is generally a small term that serves a grammatical or logical function, e.g. 'and', 'of', 'since', etc. At some point, this class might be broken up into the subclasses 'Connective', 'Preposition', etc. Note that the class ParticleWord includes both personal and possessive pronouns, e.g. 'she', 'hers', 'it', 'its', etc. A Certificate that expresses the content of an invention that has been accorded legal protection by a governemental entity. A disordered process, activity, or state of the Organism as a whole, of a body system or systems, or of multiple Organs or Tissues. Included here are normal responses to a negative stimulus as well as patholologic conditions or states that are less specific than a disease. Pathologic functions frequently have systemic effects. Sensing some aspect of the material world. Note that the agent of this sensing is assumed to be an Animal. A Series whose elements are published separately and on a periodic basis. A Residence where people live, i.e. where people have a home. A set of Words in a Language which form a unit, i.e. express a meaning in the Language. An entity that has a location in space-time. Note that locations are themselves understood to have a location in space-time. A PhysicalQuantity is a measure of some quantifiable aspect of the modeled world, such as 'the earth's diameter' (a constant length) and 'the stress in a loaded deformable solid' (a measure of stress, which is a function of three spatial coordinates). All PhysicalQuantities are either ConstantQuantities or FunctionQuantities. Instances of ConstantQuantity are dependent on a UnitOfMeasure, while instances of FunctionQuantity are Functions that map instances of ConstantQuantity to other instances of ConstantQuantity (e.g., TimeDependentQuantities are FunctionQuantities). Although the name and definition of PhysicalQuantity is borrowed from physics, PhysicalQuantities need not be material. Aside from the dimensions of length, time, velocity, etc., nonphysical dimensions such as currency are also possible. Accordingly, amounts of money would be instances of PhysicalQuantity. PhysicalQuantities are distinguished from Numbers by the fact that the former are associated with a dimension of measurement. The physical state of an Object. There are three reified instances of this Class: Solid, Liquid, and Gas. Physical changes are not characterized by the transformation of one substance into another, but rather by the change of the form (physical states) of a given substance. For example, melting an iron nail yields a substance still called iron. A normal process of an Organism or part of an Organism. English unit of volume equal to 1/2 of a Quart. A specification of a sequence of Processes which is intended to satisfy a specified purpose at some future time. The value of an angle in a plane. Specifying a set of actions in order to meet a set of goals or objectives. An Organism having cellulose cell walls, growing by synthesis of Substances, generally distinguished by the presence of chlorophyll, and lacking the power of locomotion. AnatomicalStructures that are possessed exclusively by Plants. BodySubstances that are produced exclusively by Plants. The Class of Processes where the agent pierces the surface of the Object with an instrument. Any GovernmentOrganization that is charged with domestic enforcement of the laws of the Government. An Organization that is a subOrganization of a Government, or an Organization that is attempting to bring about some sort of political change. An OrganizationalProcess carried out by, for or against officially constituted governments. Some examples would be voting on proposed legislation, electing a government representative, or even overthrowing a government in a revolution. A powder produced by FloweringPlants that contains male gametes and is capable of fertilizing the seeds of FloweringPlants of the same species. A formal position of reponsibility within an Organization. Examples of Positions include president, laboratory director, senior researcher, sales representative, etc. Attributes characterizing the orientation of an Object, e.g. Vertical versus Horizontal, Left versus Right etc. An Integer that is greater than zero. A RealNumber that is greater than zero. English mass unit of pounds. Precipitation is the process of water molecules falling from the air to the ground, in either a liquid or frozen state. A Predicate is a sentence-forming Relation. Each tuple in the Relation is a finite, ordered sequence of objects. The fact that a particular tuple is an element of a Predicate is denoted by '(*predicate* arg_1 arg_2 .. arg_n)', where the arg_i are the objects so related. In the case of BinaryPredicates, the fact can be read as `arg_1 is *predicate* arg_2' or `a *predicate* of arg_1 is arg_2'. The Class of IntentionalPsychologicalProcesses which involve the formulation of a Proposition about a state of affairs which might be realized in the future. A Phrase that begins with a preposition and that functions as an Adjective or an Adverb. Any SocialInteraction where a CognitiveAgent or Group of CognitiveAgents attempts to make another CognitiveAgent or Group of CognitiveAgents believe something that is false. This covers deceit, affectation, impersonation, and entertainment productions, to give just a few examples. Colors which can be blended to form any color and which cannot be derived from any other colors. The Class of Mammals which are Primates. An Integer that is evenly divisible only by itself and 1. A class containing all of the Attributes relating to objective, qualitative assessments of probability, e.g. Likely and Unlikely. The Class of Relations that permit assessment of the probability of an event or situation. A sequence-dependent specification. Some examples are ComputerPrograms, finite-state machines, cooking recipes, musical scores, conference schedules, driving directions, and the scripts of plays and movies. Intuitively, the class of things that happen and have temporal parts or stages. Examples include extended events like a football match or a race, actions like Pursuing and Reading, and biological processes. The formal definition is: anything that lasts for a time but is not an Object. Note that a Process may have participants 'inside' it which are Objects, such as the players in a football match. In a 4D ontology, a Process is something whose spatiotemporal extent is thought of as dividing into temporal stages roughly perpendicular to the time-axis. An Artifact that is produced by Manufacture and that is intended to be sold. Propositions are Abstract entities that express a complete thought or a set of such thoughts. As an example, the formula '(instance Yojo Cat)' expresses the Proposition that the entity named Yojo is an element of the Class of Cats. Note that propositions are not restricted to the content expressed by individual sentences of a Language. They may encompass the content expressed by theories, books, and even whole libraries. It is important to distinguish Propositions from the ContentBearingObjects that express them. A Proposition is a piece of information, e.g. that the cat is on the mat, but a Conten