Etymology
Advertisement

mainstream (n.)

also main-stream, main stream, "principal current of a river," 1660s, from main (adj.) + stream (n.); hence, "prevailing direction in opinion, popular taste, etc.," a figurative use first attested in Carlyle (1831). Mainstream media attested by 1980 in language of U.S. leftists critical of coverage of national affairs.

Advertisement
Advertisement
Definitions of mainstream

mainstream (n.)
the prevailing current of thought;
his thinking was in the American mainstream
From wordnet.princeton.edu