coat: [13] Coat seems originally to have signified a sort of short close-fitting cloth tunic with sleeves, worn by men. Over the centuries fashion has lengthened the garment, and its male exclusivity has disappeared (originally, as a woman’s garment a coat was a skirt, a sense preserved in petticoat). The word is of Germanic origin (it has been traced back to Frankish *kotta), but it reached English via Old French cote.
early 14c., "outer garment," from Old French cote "coat, robe, tunic, overgarment," from Frankish *kotta "coarse cloth" or some other Germanic source (compare Old Saxon kot "woolen mantle," Old High German chozza "cloak of coarse wool," German Kotze "a coarse coat"), of unknown origin. Transferred to animal's natural covering late 14c. Extended 1660s to a layer of any substance covering any surface. Spanish, Portuguese cota, Italian cotta are Germanic loan-words.
