What is "cerebral hemispheres"

Hemisphere \Hem"i*sphere\, n. [L. hemisphaerium, Gr. ?; ? half = ? sphere: cf. F. h['e]misph[`e]re. See Hemi-, and Sphere.]

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.

   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hemispheres (Physics), two hemispherical cups forming, when placed together, a cavity from which the air can be withdrawn by an air pump; -- used to illustrate the pressure of the air.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.

n. (cerebral hemisphere English)