beret (n.)

also berret, "round, flat, woolen cap," originally worn by Basque peasants, 1827 as a fashionable accessory, from French béret, 19c., from dialect of Béarn, from Old Gascon berret "cap," from Medieval Latin birretum, diminutive of Late Latin birrus "a large hooded cloak," a word perhaps of Gaulish origin. For the clerical version, see biretta.