'intra-cranial' originates from the Latin prefix 'intra-' meaning 'within' and from Greek 'kranion' meaning 'skull', combined in New Latin/medical formation as 'intracranial'.

'cranial' comes from Latin 'cranium', itself from Greek 'kranion'; Latin and Medieval Latin forms produced English 'cranial', and the combining prefix 'intra-' was later attached in medical usage to form 'intracranial'.

Initially related broadly to the skull ('of the skull'), the term became specialized in medicine to mean specifically 'located within the skull/cranial cavity'.