Source : Webster's Revised Unabridged Dictionary (1913)

Rifle \Ri"fle\, n. [Akin to Dan. rifle, or riffel, the rifle of
   a gun, a chamfer (cf. riffel, riffelb["o]sse, a rifle gun,
   rifle to rifle a gun, G. riefeln, riefen, to chamfer,
   groove), and E. rive. See {Rive}, and cf. {Riffle}, {Rivel}.]
   1. A gun, the inside of whose barrel is grooved with spiral
      channels, thus giving the ball a rotary motion and
      insuring greater accuracy of fire. As a military firearm
      it has superseded the musket.

   2. pl. (Mil.) A body of soldiers armed with rifles.

   3. A strip of wood covered with emery or a similar material,
      used for sharpening scythes.

   {Rifle pit} (Mil.), a trench for sheltering sharpshooters.