/ Dictionary / Index O ontology: Meaning and Definition of Find definitions for: on•tol•o•gy Pronunciation: (on-tol'u-jē), [key] — n. the branch of metaphysics that studies the nature of existence or being as such. (loosely) metaphysics. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: ontology (Thesaurus) ontologize onus Related Content Daily Word Quiz: cautious Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language