/ Dictionary / Index L lact-: Meaning and Definition of Find definitions for: lact- Pronunciation: [key] var. ofbefore a vowel: lactalbumin. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. La Crosse lactalbumin Related Content Daily Word Quiz: rustic Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language