"trite, commonplace," 1840, from French banal, "belonging to a manor; common, hackneyed, commonplace," from Old French banel "communal" (13c.), from ban "decree; legal control; announcement; authorization; payment for use of a communal oven, mill, etc.," from a Germanic source, from Proto-Germanic *bannan "to speak publicly, used of different kinds of proclamations (see ban (v.)).
The sense evolved from the word's use in designating things like ovens or mills that were used in common by serfs, or else in reference to compulsory feudal military service; in either case it was generalized in French through "open to everyone" to "commonplace, ordinary," to "trite, petty." The word was earlier used in English with a sense "pertaining to compulsory feudal service" (1753). Related: Banalize; banalization.