Source : Webster's Revised Unabridged Dictionary (1913)

Whitworth gun \Whit"worth gun`\ (Gun.)
   A form of rifled cannon and small arms invented by Sir Joseph
   Whitworth, of Manchester, England.

   Note: In Mr. Whitworth's system, the bore of the gun has a
         polygonal section, and the twist is rapid. The ball,
         which is pointed in front, is made to fit the bore
         accurately, and is very much elongated, its length
         being about three and one half times as great as its
         diameter. --H. L. Scott.