Hemisphere

Pronunciation

• RP IPA: /ˈhÉ›mɪsfɪə/
• US enPR: hÄ•'mÄ­sfîr, IPA: /ˈhÉ›mɪsfɪər/

Alternative forms

• hemisphære archaic

Origin

From Latin hemisphaerium, from Ancient Greek ἡμισφαίριον (hēmisphairion), from ἡμι- (hēmi-, "half") + σφαῖρα (sphaira, "").

Full definition of hemisphere

Noun

1. (astronomy, astrology) Half of the celestial sphere, as divided by either the ecliptic or the celestial equator from 14th c..
2. (figuratively) A realm or domain of activity 1503.
3. (geography) Half of the Earth, such as the Northern Hemisphere, Southern Hemisphere, Western Hemisphere or Eastern Hemisphere, Land Hemisphere, Water Hemisphere etc. 1550s.
4. (geometry) Any half-sphere, formed by a plane intersecting the center of a sphere. 1580s.
5. (cartography) A map or projection of a celestial or terrestrial hemisphere 1706.
6. (anatomy) Either of the two halves of the cerebrum. 1804.

Synonyms

• (astronomy: half of the celestial sphere) celestial hemisphere
• (geography: half of the terrestrial sphere) terrestrial hemisphere
• (figuratively: a domain of thought or action) sphere
• (geometry: half of a sphere) half-sphere, half sphere
• (anatomy: either of the two lobes of the cerebellum) cerebral hemisphere
• (cartography: a map showing a projection of a hemisphere) planisphere