hem|i|sphere

hem|i|sphere «HEHM uh sfihr», noun.

1. a half sphere or globe, formed by a plane passing through the center.

2. a) half of the earth's surface. North America and South America are in the Western Hemisphere; Europe, Asia, Africa, and Australia are in the Eastern Hemisphere. All countries north of the equator are in the Northern Hemisphere; those south of the equator are in the Southern Hemisphere. b) half of the earth, based on a division into a land hemisphere and a water hemisphere. The land hemisphere includes half of the earth with the most land. Its center lies near London, England. The other half of the earth, mostly water, makes up the water hemisphere. Its center lies near New Zealand.

3. half of the celestial sphere, as divided by the celestial equator, the ecliptic, or the horizon.

4. a map or model of half the terrestrial or celestial globe.

5. Figurative. an area of action, life, or thought; sphere; circle.

6. Anatomy. either of the two parts that together form most of the cerebrum; cerebral hemisphere.

╂[< Old French hemisphere, learned borrowing from Latin hēmisphaerium < Greek hēmisphaírion < hēmi- half + sphaíra sphere]