/ Dictionary / Index L lactase: Meaning and Definition of Find definitions for: lac•tase Pronunciation: (lak'tās, -tāz"), [key] — n. Biochem. an enzyme capable of hydrolyzing lactose into glucose and galactose. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: lactase (Thesaurus) lactary lactate Related Content Daily Word Quiz: profiterole Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language