switchblade knife
Defined in 1 dictionary — U.S. Code
United States Code
15 U.S.C. § 1241 — as used in this chapter
The term “switchblade knife” means any knife having a blade which opens automatically—
(1) by hand pressure applied to a button or other device in the handle of the knife, or
(2) by operation of inertia, gravity, or both.