1580s, "flexible traveling case or bag for clothes and other necessaries," from Middle French portemanteau "traveling bag," originally "court official who carried a prince's mantle" (1540s), from porte, imperative of porter "to carry" (see porter (n.1)) + manteau "cloak" (see mantle (n.)). Sometimes partially Englished as portmantle.

Portmanteau word "word blending the sound of two different words" (1882) was coined by "Lewis Carroll" (Charles L. Dodgson, 1832-1898) for the sort of words he invented for "Jabberwocky," on the notion of "two meanings packed up into one word." As a noun in this sense from 1872.