/ Dictionary / Index M mainstreamer: Meaning and Definition of Find definitions for: main•stream•er Pronunciation: (mān'strē"mur), [key] — n. a member of the mainstream. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. mainstream mainstreaming Related Content Daily Word Quiz: perspicacious Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language