noun

• (astronomy, astrology) Half of the celestial sphere, as divided by either the ecliptic or the celestial equator .
• (figuratively) A realm or domain of activity .
• (geography) Half of the Earth, such as the Northern Hemisphere, Southern Hemisphere, Western Hemisphere or Eastern Hemisphere, Land Hemisphere, Water Hemisphere etc. .
• (geometry) Any half-sphere, formed by a plane intersecting the center of a sphere. .
• (cartography) A map or projection of a celestial or terrestrial hemisphere .
• (anatomy) Either of the two halves of the cerebrum. .