n., A knife with a blade that can be deployed by depressing a button, switch, or hidden mechanism. Switch-blade knives
vary in design; some deploy the blade in a linear fashion from the handle ("out the front") while others swing a blade
out in an arc from the side of the knife handle ("side opener").

Switch-blade or "automatic" knives vary
in legality from region to region. Gang
use of such knives in the American 1950s
prompted bans on such knives in several states that remain in force today.

Switch-blade knives are illegal in some
nations, such as Canada.

The term "automatic knife" has replaced
"switch-blade" in some knife collector
circles when describing modern designs.

Also "switchblade".