/ Dictionary / Index O onomastics: Meaning and Definition of Find definitions for: on•o•mas•tics Pronunciation: (on"u-mas'tiks), [key] — n. (used with a sing. v.) the study of the origin, history, and use of proper names. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: onomastics (Thesaurus) onomasticon onomatology Related Content Daily Word Quiz: soporific Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language