ontologies

Noun

ontology (countable and uncountable, plural ontologies)

1. (uncountable) The branch of metaphysics that addresses the nature or essential characteristics of being and of things that exist; the study of being qua being.
   • [Martin] Heidegger's concern […] was with ontology, the nature of beings, above all humans. The central question for him was "What is being? What is it for something to be?" He tackled this question not by way of the sciences, but by way of an examination of our prescientific daily life. We are, he...2014 April 12, Michael Inwood, “Martin Heidegger: the philosopher who fell for Hitler [print version: Hitler's philosopher]”, in The Daily Telegraph (Review), London, archived from the original on 13...
2. (uncountable) In a subject view, or a world view, the set of conceptual or material things or classes of things that are recognised as existing, or are assumed to exist in context, and their interrelations; in a body of theory, the ontology comprises the domain of discourse, the things that are defined as existing, together with whatever emerges from their mutual implications.
   • Meronym: taxonomy
3. (countable) The theory of a particular philosopher or school of thought concerning the fundamental types of entity in the universe.
   • The answer to the controversial question of whether Aristotle's ontology includes non-substantial particulars, then, is that it does.2000, C. D. C. Reeve, Substantial Knowledge: Aristotle's Metaphysics, Hackett Publishing, page 97
4. A logical system involving theory of classes, developed by Stanislaw Lesniewski (1886-1939).
5. (countable) A structure of concepts or entities within a domain, organized by relationships; a system model.