A pin or wedge inserted through a slot to hold machine parts together; a cotter.
A split pin, the ends of which project through an object being fastened and are bent back to hold it in place.
A stationery fastening device made of thin, soft metal, with a round head and a flat, split shank, which is spread after insertion in a hole in a stack of pages, in much the same way as a cotter pin or a split rivet.
Any similar stationery fastening device.