jacket (n.) Look up jacket at Dictionary.com
mid-15c., "short garment for men," from Middle French jaquet "short coat with sleeves," diminutive of Old French jaque, a kind of tunic, probably from Jacque, the male proper name, also the generic name of a French peasant (see jacquerie), but possibly associated with jaque (de mailles) "short, tight-fitting coat," originally "coat of mail," from Spanish jaco, from Arabic shakk "breastplate." Iakke "a short, close-fitting stuffed or quilted tunic, often serving as a defensive garment" is attested in English from late 14c., and by c.1400 was being used for "woman's short tunic." Meaning "paper wrapper of a book" is first attested 1894.