crotal (crotale) / crotyl [ˈkro:tɪl]
crotal (crotale) – n. – 1. crotalum – one of a pair of small cymbals or rods used like castanets by dancers in antiquity; 2. a small, spherical, metal rattle (as on a harness); 3. similar musical instruments
crotyl – n. – the butenyl radical, CH3=CHCH2, called also 2-butenyl