Source : Webster's Revised Unabridged Dictionary (1913)

Carbine \Car"bine\, n. [F. carbine, OF. calabrin carabineer (cf.
   Ot. calabrina a policeman), fr. OF & Pr. calabre, OF. cable,
   chable, an engine of war used in besieging, fr. LL.
   chadabula, cabulus, a kind of projectile machine, fr. Gr. ? a
   throwing down, fr. ? to throw; ? down + ? to throw. Cf.
   {Parable}.] (Mil.)
   A short, light musket or rifle, esp. one used by mounted
   soldiers or cavalry.

Source : WordNet®

carbine
     n : light automatic rifle