/ Dictionary / Index O oniomania: Meaning and Definition of Find definitions for: o•ni•o•ma•ni•a Pronunciation: (ō"nē-u-mā'nē-u, -mān'yu), [key] — n. an uncontrollable desire to buy things. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. -onic onion Related Content Daily Word Quiz: cygnet Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language