late 14c., "observation as the source of knowledge; actual observation; an event which has affected one," from Old French esperience "experiment, proof, experience" (13c.), from Latin experientia "a trial, proof, experiment; knowledge gained by repeated trials," from experientem (nominative experiens) "experienced, enterprising, active, industrious," present participle of experiri "to try, test," from ex "out of" (see ex-) + peritus "experienced, tested," from PIE *per-yo-, suffixed form of root *per- (3) "to try, risk." Meaning "state of having done something and gotten handy at it" is from late 15c.