'extracranial' originates from Latin and Greek, specifically the Latin word 'extra' and the Greek word 'kranion', where 'extra' meant 'outside' and 'kranion' meant 'skull'.

'extracranial' changed from formations in New/Modern Latin combining 'extra-' (Latin) and 'cranialis'/'cranium' (from Latin 'cranium' < Greek 'kranion') and eventually became the modern English word 'extracranial'.

Initially, it meant 'outside the skull', and over time this anatomical/medical meaning has remained essentially the same.