Source : Webster's Revised Unabridged Dictionary (1913)

Tunnage \Tun"nage\ (?; 48), n. [From {Tun}; cf. {Tonnage}.]
   See {Tonnage}.

Source : WordNet®

tunnage
     n : a tax imposed on ships that enter the US; based on the
         tonnage of the ship [syn: {tonnage}, {tonnage duty}]