Sokka (englanniksi)

cotter pin (s: US)
split pin (s: UK / metal fastener with two tines that are bent during installation, used e.g. to hold cotters in their place)
safety pin (s: pin of a hand grenade that prevents accidental detonation)
Any similar part meant to secure e.g. a machine part without having to withstand the load that affects the secured part (s)