Source : Webster's Revised Unabridged Dictionary (1913)

Ketch \Ketch\ (k[e^]ch), n. [Prob. corrupted fr. Turk.
   q[=a][imac]q : cf. F. caiche. Cf. {Ca["i]que}.] (Naut.)
   An almost obsolete form of vessel, with a mainmast and a
   mizzenmast, -- usually from one hundred to two hundred and
   fifty tons burden.

   {Bomb ketch}. See under {Bomb}.

Ketch \Ketch\, n.
   A hangman. See {Jack Ketch}.

Ketch \Ketch\, v. t. [See {Catch}.]
   To catch. [Now obs. in spelling, and colloq. in
   pronunciation.]

         To ketch him at a vantage in his snares. --Spenser.

Source : WordNet®

ketch
     n : a sailing vessel with two masts; the mizzen is forward of
         the rudderpost