Source : Webster's Revised Unabridged Dictionary (1913)

Portmanteau \Port*man"teau\, n.; pl. {Portmanteaus}. [F.
   porte-manteau; porter to carry + manteau a cloak, mantle. See
   {Port} to carry, and {Mantle}.]
   A bag or case, usually of leather, for carrying wearing
   apparel, etc., on journeys. --Thackeray.

Source : WordNet®

portmanteau
     n 1: a new word formed by joining two others and combining their
          meanings; "`smog' is a blend of `smoke' and `fog'";
          "`motel' is a portmanteau word made by combining `motor'
          and `hotel'"; "`brunch' is a well-known portmanteau"
          [syn: {blend}, {portmanteau word}]
     2: a large travelling bag made of stiff leather [syn: {Gladstone},
         {Gladstone bag}]
     [also: {portmanteaux} (pl)]