HEMISPHERE

(Gr. i^/Mtrvs, and (r<pa.7^ot,, a sphere.) In Geometry, the half of a sphere, bisected by a plane pa ing through its centre. In Astronomy, it is used to designate the half of the terrestrial sphere divided by the equator. Hemisphere also denotes a map or projection of half the terrestrial or celestial sphere on a plane. [s. 562]