Maryland Code, Criminal Law § 4-105

(1) a knife or a penknife having a blade that opens automatically by hand pressure applied to a button, spring, or other device in the handle of the knife, commonly called a switchblade knife or a switchblade penknife; or

(2) a device that is designed to propel a knife from a metal sheath by means of a high-compression ejector spring, commonly called a shooting knife.