hemisphere

anatomy: either of the two lobes of the cerebellum

any half-sphere

astronomy: half of the celestial sphere

cartography: a map showing a projection of a hemisphere

cartography: map or projection of a celestial or terrestrial hemisphere

figuratively: a domain of thought or action

geography: half of the terrestrial sphere

geometry: half of a sphere

half of the celestial sphere

half of the Earth

realm or domain of activity