Etymology tree Proto-Indo-European *koḱs- Proto-Indo-European *-h₂ Proto-Indo-European *-eh₂ Proto-Indo-European *kóḱseh₂ Proto-Italic *koksā Latin coxalbor. English coxa Learned borrowing from Latin coxa, from Proto-Italic *koksā, from Proto-Indo-European *kóḱseh₂, from *koḱs- (“joint, limb”) + *-eh₂. Doublet of cuisse.