N.Y. Comp. Codes R. & Regs. tit. 8, § 590.2 – Definitions.

(a) The terms firearm, rifle and shotgun as used in this Part shall be defined as in the Penal Law.
(b) Weapon shall mean those weapons described in section 265.01 of the Penal Law.
(c) Airgun shall mean any rifle or pistol operated by compressed air that fires a metallic projectile.