/ Dictionary / Index L ligase: Meaning and Definition of Find definitions for: li•gase Pronunciation: (lī'gās, -gāz), [key] — n. Biochem. any of a class of enzymes that catalyze the joining of two molecules by formation of a covalent bond accompanied by the hydrolysis of ATP. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. ligand ligate Related Content Daily Word Quiz: exasperate Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language