/ Dictionary / Index L lyase: Meaning and Definition of Find definitions for: ly•ase Pronunciation: (lī'ās, -āz), [key] — n. Biochem. any of various enzymes, as decarboxylase, that catalyze reactions involving the formation of or addition to a double bond. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. lyard Lyautey Related Content Daily Word Quiz: lyceum Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language