'hemisphere' originates from Greek, specifically the word 'hēmisphairion,' where 'hēmi-' meant 'half' and 'sphaira' meant 'sphere.'

'hēmisphairion' transformed into the Latin word 'hemisphaerium,' and eventually became the modern English word 'hemisphere' through Old French.

Initially, it meant 'half of a sphere,' and this meaning has largely remained the same in modern usage.