'antihemisphere' is formed from the Greek-derived prefix 'anti-' (from Greek 'anti', meaning 'against' or 'opposite') and 'hemisphere' (from Greek 'hemisphaira', literally 'half-sphere', via Latin 'hemisphaerium').

'hemisphere' entered English via Latin 'hemisphaerium' from Greek 'hemisphaira'; the prefix 'anti-' comes from Greek 'anti-'. The compound 'antihemisphere' is a modern English formation combining these elements to denote the opposite half of a sphere (especially the Earth).

The components originally meant 'opposite' (anti-) and 'half-sphere' (hemisphere); together they have consistently meant 'the opposite half of a sphere' and this core meaning remains unchanged in modern usage.