Ontology

4 definitions found

From The Collaborative International Dictionary of English v.0.48 [gcide]:

  Ontology \On*tol"o*gy\, n. [Gr. ? the things which exist
     (pl.neut. of ?, ?, being, p. pr. of ? to be) + -logy: cf. F.
     ontologie.]
     1. That department of the science of metaphysics which
        investigates and explains the nature and essential
        properties and relations of all beings, as such, or the


        principles and causes of being.
        [1913 Webster]
  
     2. (Computers) A systematic arrangement of all of the
        important categories of objects or concepts which exist in
        some field of discourse, showing the relations between
        them. When complete, an ontology is a categorization of
        all of the concepts in some field of knowledge, including
        the objects and all of the properties, relations, and
        functions needed to define the objects and specify their
        actions. A simplified ontology may contain only a
        hierarchical classification (a {taxonomy}) showing the
        type subsumption relations between concepts in the field
        of discourse. An ontology may be visualized as an abstract
        graph with nodes and labeled arcs representing the objects
        and relations.
  
     Note: The concepts included in an ontology and the
           hierarchical ordering will be to a certain extent
           arbitrary, depending upon the purpose for which the
           ontology is created. This arises from the fact that
           objects are of varying importance for different
           purposes, and different properties of objects may be
           chosen as the criteria by which objects are classified.
           In addition, different degrees of aggregation of
           concepts may be used, and distinctions of importance
           for one purpose may be of no concern for a different
           purpose.
           [PJC]

From WordNet (r) 2.0 [wn]:

  ontology
       n : the metaphysical study of the nature of being and existence

From Moby Thesaurus II by Grady Ward, 1.0 [moby-thes]:

  28 Moby Thesaurus words for "ontology":
     aesthetics, axiology, casuistry, cosmology, epistemology, ethics,
     existentialism, first philosophy, gnosiology, logic,
     mental philosophy, metaphysics, moral philosophy, phenomenology,
     philosophastry, philosophic doctrine, philosophic system,
     philosophic theory, philosophical inquiry,
     philosophical speculation, philosophy, school of philosophy,
     school of thought, science of being, sophistry, theory of beauty,
     theory of knowledge, value theory
  
  

From The Free On-line Dictionary of Computing (27 SEP 03) [foldoc]:

  ontology
       
          1.  A systematic account of Existence.
       
          2.  (From philosophy) An explicit
          formal specification of how to represent the objects, concepts
          and other entities that are assumed to exist in some area of
          interest and the relationships that hold among them.
       
          For {AI} systems, what "exists" is that which can be
          represented.  When the {knowledge} about a {domain} is
          represented in a {declarative language}, the set of objects
          that can be represented is called the {universe of discourse}.
          We can describe the ontology of a program by defining a set of
          representational terms.  Definitions associate the names of
          entities in the {universe of discourse} (e.g. classes,
          relations, functions or other objects) with human-readable
          text describing what the names mean, and formal {axioms} that
          constrain the interpretation and well-formed use of these
          terms.  Formally, an ontology is the statement of a {logical
          theory}.
       
          A set of {agents} that share the same ontology will be able to
          communicate about a domain of discourse without necessarily
          operating on a globally shared theory.  We say that an agent
          commits to an ontology if its observable actions are
          consistent with the definitions in the ontology.  The idea of
          ontological commitment is based on the {Knowledge-Level}
          perspective.
       
          3.  The hierarchical structuring of
          knowledge about things by subcategorising them according to
          their essential (or at least relevant and/or cognitive)
          qualities.  See {subject index}.  This is an extension of the
          previous senses of "ontology" (above) which has become common
          in discussions about the difficulty of maintaining {subject
          indices}.
       
          (1997-04-09)