The safety catch on a gun is a device that stops you firing the gun accidentally. Eddie slipped the safety catch on his automatic back into place. a lock on a gun that stops anyone from shooting it by accident American Equivalent: safety
Prior to 1900 or so, brooches had a simple "C" catch with no locking mechanism, and the pin often extended out beyond the "C" far enough to weave back into clothing for security At the turn of the century several "safety catches" were invented and came into common used for better jewelry, so a piece that exhibits a safety catch was made in the twentieth century (Consider the possibility, however, that an old catch was replaced at some point, and look for evidence of this )
A safety catch is a secondary closure (usually on a fine bracelet or necklace) that is used in case the primary clasp opens, preventing the loss of the jewelry It is often a hinged, snapping loop that is permanently attached to one side of the clasp (often a box clasp), and, when the bracelet is closed, snaps onto the other side of the clasp