c. 1200, "piece of cloth attached to the upper end of a pole or staff," from Old French baniere "flag, banner, standard" (12c., Modern French bannière), from Late Latin bandum "standard," borrowed from Frankish or another West Germanic source, from Proto-Germanic *bandwa- "identifying sign, banner, standard," also "company under a banner" (source also of Gothic bandwa "a sign"), from suffixed form of PIE root *bha- (1) "to shine."
Formerly the standard of a king, lord, or knight, behind which his followers marched to war and to which they rallied in battle. Figurative sense of "anything displayed as a profession of principles" is from early 14c. Of newspaper headlines that stream across the top of the page, from 1913.
"a standard of judgment or criticism, rule by which opinion or conduct can be tested," 1660s, from Latinized form of Greek kriterion "means for judging, standard," from krites "judge," from PIE root *krei- "to sieve," thus "discriminate, distinguish." Used in English as a Greek word from 1610s.