/ Dictionary / Index L lactoprotein: Meaning and Definition of Find definitions for: lac•to•pro•tein Pronunciation: (lak"tō-prō'tēn, -prō'tē-in), [key] — n. any protein existing in milk. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. lacto-ovo-vegetarian lactoscope Related Content Daily Word Quiz: reticent Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language