Clasp

(Hasp). In mechanical dentistry, a hook fitted to a tooth and designed for the retention of a dental substitute or other apparatus to be worn in the mouth. In biology, an apparatus at the end of the male abdomen in certain insects, intended to grasp the female. C. -knife Rigidity, a reflex spasmodic action of the legs from increased myotatic irritability, as a result of which extension is, as it were, completed with a " spring," as in the knife.