'post-coxal' originates from Latin prefix 'post-' (meaning 'after') combined with Latin 'coxa' (from Greek 'koksa'), where 'coxa' meant 'hip' or 'haunch'.

'post-coxal' developed in scientific/technical English as a compound of 'post-' + 'coxal' in anatomical and entomological usage (19th–20th century) and has been used to describe structures located behind the coxa.

Initially it meant 'located after or behind the coxa,' and this specialized anatomical/entomological meaning has largely been retained in modern usage.