/ Dictionary / Index O onagraceous: Meaning and Definition of Find definitions for: on•a•gra•ceous Pronunciation: (on"u-grā'shus), [key] — adj. belonging to the Onagraceae, the evening primrose family of plants. Cf. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. onager on-air Related Content Daily Word Quiz: rustic Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language