Hemisphere

Part of speech: noun (n.)

1. A half sphere; one half of a sphere or globe, when divided by a plane passing through its center.

2. Half of the terrestrial globe, or a projection of the same in a map or picture.

3. The people who inhabit a hemisphere. He died . . . mourned by a hemisphere. J. P. Peters. ten Cerebral hemispheres. (Anat.) See Brain. -- Magdeburg hemispheres (Physics), two hemispherical cups forming, when placed together, a cavity from which the air can be withdrawn by an air pump; -- used to illustrate the pressure of the air. So called because invented by Otto von Guericke at Magdeburg.