'intra-galactic' originates from Latin, specifically the word 'intra', and from Greek, specifically the word 'galaktikos', where 'intra' meant 'within' and 'galaktikos' related to 'galaxias' meaning 'milky'.

'galactic' changed from the Greek word 'galaktikos' (related to 'galaxias'), passed into Latin and later into Middle English as 'galaxy'/'galactic'; the prefix 'intra-' comes from Latin 'intra' and was later combined with 'galactic' to form 'intra-galactic' in modern English usage.

Initially, 'galactic' often referred specifically to the Milky Way ('the milky' galaxy); over time, the element broadened to mean 'relating to any galaxy', so 'intra-galactic' now means 'within a single galaxy' rather than only the Milky Way.