"house of prostitution," c.1300, from O.Fr. bordel
"small hut, cabin; brothel" (12c.), dim. of borde
"hut made of planks," from Frankish *bord
"wooden board" or some other Germanic source related to board
(1). The modern form is a result of the word being borrowed from French by Italian, then passed back with a suffix and re-borrowed into English by 1590s.