Where does “cossinum” come from?

cossinum (Latin) comes from Latin coxa, from Proto-Indo-European koḱs- — joint.

Ancestry of “cossinum”, step by step

Step	Language	Word	Meaning
1	Latin	coxa	hip , hipbone; thigh
2	Proto-Indo-European	koḱs-	joint

cossinum — Etymology, Origin & Word History | Etymology Explorer