Source : Webster's Revised Unabridged Dictionary (1913)

Firearm \Fire"arm`\, n.
   A gun, pistol, or any weapon from a shot is discharged by the
   force of an explosive substance, as gunpowder.

Source : WordNet®

firearm
     n : a portable gun; "he wore his firearm in a shoulder holster"
         [syn: {piece}, {small-arm}]