gravity knife

gravity +‎ knife. From being a folding knife that could be opened by allowing gravity to draw out the blade.

gravity knife (plural gravity knives)

1. A type of knife that with the press of a button, allows the blade to drop out of the handle, and then quickly opened up full, for quick use, also allowing it to be flicked open with a flick of the wrist.
   1. A folding knife of this type.
   2. A telescoping knife of this type.

• paratrooper knife

(folding knife):

• button lock (a type that overlaps with gravity types)
• flick knife (open with a flick of the wrist)
• switchblade (spring-loaded opening knife)
• butterfly knife
• spring knife