/ Dictionary / Index G gramicidin: Meaning and Definition of Find definitions for: gram•i•ci•din Pronunciation: (gram"u-sīd'n), [key] — n. Pharm. a crystalline, water-insoluble antibiotic obtained from tyrothrycin by extraction, used chiefly in treating local infections caused by Gram-positive organisms. Also called Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: gramicidin (Thesaurus) gramercy gramineous Related Content Daily Word Quiz: endear Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language