crotalum
From LSJ
crŏtălum: i, n., = κρόταλον,
I a rattle, a bell, castanet, used to accompany wanton dances, P. Scip. ap. Macr. S. 2, 10; Cic. Pis. 9, 20 al.
crŏtălum, ī, n. (κρόταλον), castagnette, crotale : Scip. d. Macr. Sat. 2, 10, 7 ; Virg. Copa 2.