instance An object is an instance of a SetOrClass if it is included in that SetOrClass. An individual may be an instance of many classes, some of which may be subclasses of others. Thus, there is no assumption in the meaning of instance about specificity or uniqueness. immediateInstance An object is an immediateInstance of a SetOrClass if it is an instance of the SetOrClass and it is not an instance of a proper subclass of SetOrClass. inverse The inverse of a BinaryRelation is a relation in which all the tuples of the original relation are reversed. In other words, one BinaryRelation is the inverse of another if they are equivalent when their arguments are swapped. subclass (subclass ?CLASS1 ?CLASS2) means that ?CLASS1 is a subclass of ?CLASS2, i.e. every instance of ?CLASS1 is also an instance of ?CLASS2. A class may have multiple superclasses and subclasses. immediateSubclass A SetOrClass ?CLASS1 is an immediateSubclass of another SetOrClass ?CLASS2 just in case ?CLASS1 is a subclass of ?CLASS2 and there is no other subclass of ?CLASS2 such that ?CLASS1 is also a subclass of it. subrelation (subrelation ?REL1 ?REL2) means that every tuple of ?REL1 is also a tuple of ?REL2. In other words, if the Relation ?REL1 holds for some arguments arg_1, arg_2, ... arg_n, then the Relation ?REL2 holds for the same arguments. A consequence of this is that a Relation and its subrelations must have the same valence. In CycL, subrelation is called #$genlPreds. domain Provides a computationally and heuristicallyconvenient mechanism for declaring the argument types of a given relation. The formula (domain ?REL ?INT ?CLASS) means that the ?INT'th element of each tuple in the relation ?REL must be an instance of ?CLASS. Specifying argumenttypes is very helpful in maintaining ontologies. Representation systems can use these specifications to classify terms and check integrity constraints. If the restriction on the argument type of a Relation is not captured by a SetOrClass already defined in the ontology, one can specify a SetOrClass compositionally with the functions UnionFn, IntersectionFn, etc. domainSubclass Predicate used to specify argument type restrictions of Predicates. The formula (domainSubclass ?REL ?INT ?CLASS) means that the ?INT'th element of each tuple in the relation ?REL must be a subclass of ?CLASS. equal (equal ?ENTITY1 ?ENTITY2) is true just in case ?ENTITY1 is identical with ?ENTITY2. range Gives the range of a function. In other words, (range ?FUNCTION ?CLASS) means that all of the values assigned by ?FUNCTION are instances of ?CLASS. rangeSubclass (rangeSubclass ?FUNCTION ?CLASS) means that all of the values assigned by ?FUNCTION are subclasses of ?CLASS. valence Specifies the number of arguments that a relation can take. If a relation does not have a fixed number of arguments, it does not have a valence and it is an instance of VariableArityRelation. For example, holds is a VariableArityRelation. documentation A relation between objects in the domain of discourse and strings of natural language text. The domain of documentation is not constants (names), but the objects themselves. This means that one does not quote the names when associating them with their documentation. disjoint Classes are disjoint only if they share no instances, i.e. just in case the result of applying IntersectionFn tothem is empty. disjointRelation This predicate relates any number of Relations. (disjointRelation @ROW) means that any two relations in @ROW have no tuples in common. As a consequence, the intersection of all of the relations in @ROW is the null set. contraryAttribute A contraryAttribute is a set of Attributes such that something can not simultaneously have more than one of these Attributes. For example, (contraryAttribute Pliable Rigid) means that nothing can be both Pliable and Rigid. exhaustiveAttribute This predicate relates a Class to a set of Attributes, and it means that the elements of this set exhaust the instances of the Class. For example, (exhaustiveAttribute PhysicalState Solid Fluid Liquid Gas) means that there are only three instances of the class PhysicalState, viz. Solid, Fluid, Liquid, and Gas. exhaustiveDecomposition An exhaustiveDecomposition of a Class C is a set of subclasses of C such that every instance of C is an instance of one of the subclasses in the set. Note: this does not necessarily mean that the elements of the set are disjoint (see partition - a partition is a disjoint exhaustive decomposition). disjointDecomposition A disjointDecomposition of a Class C is a set of subclasses of C that are mutually disjoint. partition A partition of a class C is a set of mutually disjoint classes (a subclass partition) which covers C. Every instance of C is an instance of exactly one of the subclasses in the partition. relatedInternalConcept Means that the two arguments are related concepts within the SUMO, i.e. there is a significant similarity of meaning between them. To indicate a meaning relation between a SUMO concept and a concept from another source, use the Predicate relatedExternalConcept. relatedExternalConcept Used to signify a three-place relation between a concept in an external knowledge source, a concept in the SUMO, and the name of the other knowledge source. synonymousExternalConcept (synonymousExternalConcept ?STRING ?THING ?LANGUAGE) means that the SUMO concept ?THING has the same meaning as ?STRING in ?LANGUAGE. subsumingExternalConcept (subsumingExternalConcept ?STRING ?THING ?LANGUAGE) means that the SUMO concept ?THING subsumes the meaning of ?STRING in ?LANGUAGE, i.e. the concept ?THING is broader in meaning than ?STRING. subsumedExternalConcept (subsumedExternalConcept ?STRING ?THING ?LANGUAGE) means that the SUMO concept ?THING is subsumed by the meaning of ?STRING in ?LANGUAGE, i.e. the concept ?THING is narrower in meaning than ?STRING. subAttribute Means that the second argument can be ascribed to everything which has the first argument ascribed to it. successorAttribute (successorAttribute ?ATTR1 ?ATTR2) means that ?ATTR2 is the Attribute that comes immediately after ?ATTR1 on the scale that they share. successorAttributeClosure The transitive closure of successorAttribute. (successorAttributeClosure ?ATTR1 ?ATTR2) means that there is a chain of successorAttribute assertions connecting ?ATTR1 and ?ATTR2. entails The operator of logical entailment. (entails ?FORMULA1 ?FORMULA2) means that ?FORMULA2 can be derived from ?FORMULA1 by means of the proof theory of SUO-KIF. AssignmentFn If F is a Function with a value for the objects denoted by N1,..., NK, then (AssignmentFn F N1 ... NK) is the value of applying F to the objects denoted by N1,..., NK. Otherwise, the value is undefined. holds (holds P N1 ... NK) is true just in case the tuple of objects denoted by N1,..., NK is an element of the Relation P. PowerSetFn (PowerSetFn ?CLASS) maps the SetOrClass ?CLASS to the SetOrClass of all subclasses of ?CLASS. Entity The universal class of individuals. This is the root node of the ontology. Thing Physical An entity that has a location in space-time. Note that locations are themselves understood to have a location in space-time. Object 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. SelfConnectedObject A SelfConnectedObject is any Object that does not consist of two or more disconnected parts. FrontFn A Function that maps an Object to the side that generally receives the most attention or that typically faces the direction in which the Object moves. Note that this is a partial function, since some Objects do not have sides, e.g. apples and spheres. Note too that the range of this Function is indefinite in much the way that ImmediateFutureFn and ImmediatePastFn are indefinite. Although this indefiniteness is undesirable from a theoretical standpoint, it does not have significant practical implications, since there is widespread intersubjective agreement about the most common cases. BackFn A Function that maps an Object to the side that is opposite the FrontFn of the Object. Note that this is a partial function, since some Objects do not have sides, e.g. apples and spheres. Note too that the range of this Function is indefinite in much the way that ImmediateFutureFn and ImmediatePastFn are indefinite. Although this indefiniteness is undesirable from a theoretical standpoint, it does not have significant practical implications, since there is widespread intersubjective agreement about the most common cases. part The basic mereological relation. All other mereological relations are defined in terms of this one. (part ?PART ?WHOLE) simply means that the Object ?PART is partof the Object ?WHOLE. Note that, since part is a ReflexiveRelation, every Object is a part of itself. properPart (properPart ?OBJ1 ?OBJ2) means that ?OBJ1 is a part of ?OBJ2 other than ?OBJ2 itself. This is a TransitiveRelation and AsymmetricRelation (hence an IrreflexiveRelation). piece A specialized common sense notion of part for arbitrary parts of Substances. Quasi-synonyms are: chunk, hunk, bit, etc. Compare component, another subrelation of part. component A specialized common sense notion of part for heterogeneous parts of complexes. (component ?COMPONENT ?WHOLE) means that ?COMPONENT is a component of ?WHOLE. Examples of component include the doors and walls of a house, the states or provinces of a country, or the limbs and organs of an animal. Compare piece, which is also a subrelation of part. material (material ?SUBSTANCE ?OBJECT) means that ?OBJECT is structurally made up in part of ?SUBSTANCE. This relation encompasses the concepts of 'composed of', 'made of', and 'formed of'. For example, plastic is a material of my computer monitor. Compare part and its subrelations, viz component and piece. contains The relation of spatial containment for two separable objects. When the two objects are not separable (e.g. an automobile and one of its seats), the relation of part should be used. (contains ?OBJ1 ?OBJ2) means that the SelfConnectedObject ?OBJ1 has a space (i.e. a Hole) which is at least partially filled by ?OBJ2. Substance An Object in which every part is similar to every other in every relevant respect. More precisely, something is a Substance when it has only arbitrary pieces as parts - any parts have properties which are similar to those of the whole. Note that a Substance may nonetheless have physical properties that vary. For example, the temperature, chemical constitution, density, etc. may change from one part to another. An example would be a body of water. SyntheticSubstance Any Substance that is the result of an IntentionalProcess, i.e. any substance that is created by Humans. NaturalSubstance Any Substance that is not the result of an IntentionalProcess, i.e. any substance that occurs naturally. PureSubstance The Class of Substances with constant composition. A PureSubstance can be either an element (ElementalSubstance) or a compound of elements (CompoundSubstance). Examples: Table salt (sodium chloride, NaCl), sugar (sucrose, C_{12}H_{22}O_{11}), water (H_2O), iron (Fe), copper (Cu), and oxygen (O_2). ElementalSubstance 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. Metal 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. Atom An extremely small unit of matter that retains its identity in Chemical reactions. It consists of an AtomicNucleus and Electrons surrounding the AtomicNucleus. SubatomicParticle The class of ElementalSubstances that are smaller than Atoms and compose Atoms. AtomicNucleus The core of the Atom. It is composed of Protons and Neutrons. Electron SubatomicParticles that surround the AtomicNucleus. They have a negative charge. Proton Components of the AtomicNucleus. They have a positive charge. Neutron Components of the AtomicNucleus. They have no charge. CompoundSubstance 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). Mixture 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. CorpuscularObject A SelfConnectedObject whose parts have properties that are not shared by the whole. Region A topographic location. Regions encompass surfaces of Objects, imaginary places, and GeographicAreas. Note that a Region is the only kind of Object which can be located at itself. Note too that Region is not a subclass of SelfConnectedObject, because some Regions, e.g. archipelagos, have parts which are not connected with one another. Collection 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. member A specialized common sense notion of part for uniform parts of Collections. For example, each sheep in a flock of sheep would have the relationship of member to the flock. subCollection (subCollection ?COLL1 ?COLL2) means that the Collection ?COLL1 is a proper part of the Collection ?COLL2. ContentBearingPhysical Any Object or Process thatexpresses content. This covers Objects that contain a Proposition,such as a book, as well as ManualSignLanguage, which may similarlycontain a Proposition. ContentBearingProcess Any Process, for example ManualHumanLanguage, which may contain a Proposition. ContentBearingObject 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. SymbolicString The Class of alphanumeric sequences. Character 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. containsInformation A subrelation of represents. This predicate relates a ContentBearingPhysical to the Proposition that is expressed by the ContentBearingPhysical. Examples include the relationships between a physical novel and its story and between a printed score and its musical content. Icon This is the subclass of ContentBearingPhysical 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. MotionPicture A ContentBearingObject which depicts motion (and which may have an audio or text component as well). This Class covers films, videos, etc. LinguisticExpression This is the subclass of ContentBearingPhysical which are language-related. Note that this Class encompasses both Language and the the elements of Languages, e.g. Words. Language 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. AnimalLanguage The subclass of Languages used by Animals other than Humans. ArtificialLanguage The subclass of Languages that are designed by Humans. ComputerLanguage The class of Languages designed for and interpreted by a computer. HumanLanguage The subclass of Languages used by Humans. ConstructedLanguage An ConstructedLanguage is a HumanLanguage that did not evolve spontaneously within a languagecommunity, 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 NaturalLanguage 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. ManualHumanLanguage A ManualHumanLanguage is aHumanLanguage which has as its medium gestures and movement, such as the shape, position, and movement of the hands. SpokenHumanLanguage A SpokenHumanLanguage is aHumanLanguage which has as its medium the human voice. It can also berepresented visually through writing, although not all SpokenHumanLanguages have a codified written form. Word A term of a Language that represents a concept. Formula A syntactically well-formed formula in the SUO-KIF knowledge representation language. Agent Something or someone that can act on its own and produce changes in the world. SentientAgent An Agent that has rights but may or may not have responsibilities and the ability to reason. If the latter are present, then the Agent is also an instance of CognitiveAgent. Domesticated animals are an example of SentientAgents that are not also CognitiveAgents. CognitiveAgent 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. leader (leader ?INSTITUTION ?PERSON)means that the leader of ?INSTITUTION is ?PERSON.