/ Dictionary / Index R rock cress: Meaning and Definition of Find definitions for: rock' cress" Pronunciation: [key] any of several low growing plants belonging to the genus Arabis, of the mustard family, having spikes or one-sided clusters of white, pink, or purple flowers, grown as an ornamental in rock gardens. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: rockcress (Thesaurus) rock crab rock crystal Related Content Daily Word Quiz: cetacean Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language