Definition of Firearm

An instrument used in the propulsion of shot, shell, or bullets by the action of gunpowder exploded within it. A weapon which acts by force of gunpowder. This word comprises all sorts of guns, fowling-pieces, blunderbusses, pistols, etc. In addition, grenade shells, fuses, and powder may be considered "firearm” even though disassembled. U. S. v. Shafer, C.A.I11., 445 F.2d 579, 583.

The term "firearm” means any weapon which is designed to or may readily be converted to expel any projectile by the action of an explosive; or the frame or receiver of any such weapon. 18 U.S.C.A. §§ 232(4), 921(3).

That's the definition of Firearm in Black's Law Dictionary 6th Edition. Courtesy of

Official tim editorial.