• WordNet 3.6
    • n ontology the metaphysical study of the nature of being and existence
    • n ontology (computer science) a rigorous and exhaustive organization of some knowledge domain that is usually hierarchical and contains all the relevant entities and their relations
    • ***
Webster's Revised Unabridged Dictionary
    • Ontology (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.
    • Ontology 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.
    • ***
Century Dictionary and Cyclopedia
    • n ontology The theory of being; that branch of metaphysics which investigates the nature of being and of the essence of things, both substances and accidents.
    • ***
Chambers's Twentieth Century Dictionary
    • n Ontology on-tol′o-ji the science that treats of the principles of pure being: that part of metaphysics which treats of the nature and essence of things
    • ***


Webster's Revised Unabridged Dictionary
Gr. the things which exist (pl.neut. of , , being, p. pr. of to be) + -logy,: cf. F. ontologie,
Chambers's Twentieth Century Dictionary
Gr. ōn, ontos, being pr.p. of einai, to be, logialegein, to discourse.


In literature:

The first is the physico-theological argument, the second the cosmological, the third the ontological.
"The Critique of Pure Reason" by Immanuel Kant
A discipline it is in logic, arithmetic, taste, symmetry, poetry, language, rhetoric, ontology, morals, or practical wisdom.
"Beacon Lights of History, Volume I" by John Lord
In this statement this master agrees with the philosophers who give a triplicity of essential principles as the base of ontology.
"Delsarte System of Oratory" by Various
Then the ontological proof asserts its rights unmistakably.
"The Life of Reason" by George Santayana
In most of the other sutras the burden of thought is ontology.
"The Religions of Japan" by William Elliot Griffis
A few words must be added on the ontological bearings of our argument.
"Essays on Education and Kindred Subjects" by Herbert Spencer
Is it phenomenal or ontological; ultimate or derivative?
"Thoughts on Religion" by George John Romanes
We don't even know whether it comes under the ontological or psychological departments.
"The Atlantic Monthly, Volume 18, No. 110, December, 1866" by Various
He sent one of the finest things that was ever written on the Ontology of Being to paper after paper, and it was never used.
"Better Dead" by J. M. Barrie
The author asks himself what would be the proper method, the ontological or the psychological.
"Bouvard and Pécuchet" by Gustave Flaubert

In news:

A variety of text processing tasks require or benefit from semantic resources such as ontologies and lexicons.
Description Logics, and in particular the web ontology language OWL has been proposed as an appropriate basis for computing matches between structured objects for the sake of information integration and service discovery.
The quality of ontologies (QoO) is increasingly becoming a research issue on the Semantic Web.
Ontology users may have difficulties locating the proper concepts in large ontologies, due to low quality.
Ontology mapping seeks to find semantic correspondences between similar elements of different ontologies.
Ontology mapping is critical to achieve semantic interoperability in the WWW.
An essay on the phenomenological ontology of racial preferences.
Online business matchmaker Bintro has added ontology databases Freebase and Geonames to its service.
Data models are insufficient to enable widespread system interoperability, and organizations need to develop an ontology to explain how different data elements interact, according to the chairman of the Ontology Summit.
A Semantic Similarity Function based on Hietarchical Ontologies.
Various approaches have been proposed to quantify the similarity between concepts in an ontology.
Such reasoning is, among others, useful for ontology integration, where conflicting information arises naturally.
Integration of ontologies begins with establishing mappings between their concept entries.
We map categories from the largest manually-built ontology, Cyc, onto Wikipedia articles describing corresponding concepts.
Query processing of OWL-DL ontologies is intractable in the worst case, but we present a novel technique that in practice allows for efficient querying of ontologies with large Aboxes in secondary storage.

In science:

After the user created the last sentence of this example, AceWiki detected that it contradicts the current ontology.
AceWiki: Collaborative Ontology Management in Controlled Natural Language
The user can remove this sentence again, or keep it and try to reassert it later when the rest of the ontology has changed.
AceWiki: Collaborative Ontology Management in Controlled Natural Language
Thus, ACE can be used not only as an ontology- and rule-language, but also as a query-language.
AceWiki: Collaborative Ontology Management in Controlled Natural Language
The AceWiki prototype shows how ontologies can be managed in a natural way within a wiki.
AceWiki: Collaborative Ontology Management in Controlled Natural Language
We explained how AceWiki ensures — in a very simple way — the consistency of the ontology which is the basis for other integrated reasoning services.
AceWiki: Collaborative Ontology Management in Controlled Natural Language