A latching device that prevents accidental activation of a dangerous event, an interlock. Colloquially shortened to just a safety.(noun)
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Use "safety catch" in a sentence
"“Is the safety catch on?” demanded Dr. Templett, suddenly stepping aside."
"Beadie's thumb released the safety catch as Sanderson's thumbs released the locks."
"Parlabane flipped on the gun's safety catch with his thumb, placed the pistol in Beadie's right palm, closed his fingers over it, then quickly pulled the weapon away again."