Half.

(automotive) A motor with hemispherical combustion chambers. A piston engine internal combustion engine with hemispherical piston cylinder heads.

A polyhedron containing 10 triangular faces, 15 edges, and 6 vertices.

(astronomy, astrology) Half of the celestial sphere, as divided by either the ecliptic or the celestial equator . / (figuratively) A realm or domain of activity .

The hemisphere of the Earth to the west of the Greenwich Meridian (zero degree longitude) and east of 180 degrees longitude (approximately the International Date Line). / (metonymically) The Americas.

The hemisphere of the Earth to the east of the Greenwich Meridian (zero degree longitude) and west of 180 degrees longitude (approximately the International Date Line).

The hemisphere of the Earth (or any celestial body) to the north of its equator.

The hemisphere of the Earth (or any celestial body) to the south of its equator.

(organic chemistry) Any of a class of compounds of general formula R₁R₂C(OH)OR' (where R' is not H and R₁ or R₂ is often hydrogen).

(organic chemistry) Any organic compound having both an amino and a hydroxy functional group attached to the same carbon atom; they are synthesized by reacting ammonia or an amine with an aldehyde or ketone.