Source : Webster's Revised Unabridged Dictionary (1913)

Chokebore \Choke"bore`\, n.
   1. In a shotgun, a bore which is tapered to a slightly
      smaller diameter at a short distance (usually 21/2 to 3
      inches) to the rear of the muzzle, in order to prevent the
      rapid dispersion of the shot.

   2. A shotgun that is made with such a bore.

Chokebore \Choke"bore`\, v. t. [imp. & p. p. {Chokebored}; p.
   pr. & vb. n. {Chokeboring}.]
   To provide with a chokebore.