PORTMANTEAU, a leather case or trunk for carrying articles of personal use when travelling. The typical portmanteau of the present day has two compartments which, fastened at the back by hinges, close together like a book. The original portmanteau (adopted from Fr. portemanleau, porter, to carry, manteau, cloak, mantle) was a flexible round leather case to hold a cloak or other garment and of such a shape as could conveniently be carried on a rider's saddle. In French the word was applied to a bracket or set of pegs on which to hang clothes. ( L. Dodgson (" Lewis Carroll ") in Through the Looking Glass (" The Song of the Jabberwock ") used the expression " portmanteau word " of an invented word composed of two words run together and supposed to convey humorously the combined meaning: thus " slithy " conveys slimy and lithe; " mimsy," flimsy and miserable.
Note - this article incorporates content from Encyclopaedia Britannica, Eleventh Edition, (1910-1911)