Switchblade is a type of knife that comes with a folding or spring-loaded blade that can be quickly deployed with one hand. The term "switchblade" has various synonyms that differ depending on the region and context. In some areas, it may also be referred to as an automatic knife, flick knife, push knife, or spring knife. Other less popular synonyms include swing knife, gravity knife, and butterfly knife. These knives are generally notorious for their dangerousness and the legal restrictions attached to them. Some jurisdictions prohibit their possession and use, while others require a permit or license to carry or purchase them.