/ Dictionary / Index M mutein: Meaning and Definition of Find definitions for: mu•tein Pronunciation: (my'tēn, -tē-in), [key] — n. Biochem. a mutationally altered protein. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. muted mute swan Related Content Daily Word Quiz: placid Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language