/ Dictionary / Index C crab grass: Meaning and Definition of Find definitions for: crab' grass" Pronunciation: [key] an annual grass, Digitaria sanguinalis, common in cultivated and waste grounds and often occurring as a pest weed in lawns. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: crabgrass (Thesaurus) crabeater crab louse Related Content Daily Word Quiz: arboreal Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language