/pawrt man"toh, pohrt-; pawrt'man toh", pohrt'-/ , n. , pl. portmanteaus, portmanteaux /-tohz, -toh, -tohz", -toh"/ . Chiefly Brit.
a case or bag to carry clothing in while traveling, esp. a leather trunk or suitcase that opens into two halves.
[ 1575-85; portemanteau lit., (it) carries (the) cloak; see PORT 5 , MANTLE ]