hemispheres
The globe is divided by convention into four half spheres, using the Greenwich meridian or the Equator as a reference point.
Southern Hemisphere 
Southern half of the globe in relation to the Equator.
Western Hemisphere 
Western half of the globe in relation to the prime meridian.
Northern Hemisphere 
Northern half of the globe in relation to the Equator.
Eastern Hemisphere 
Eastern half of the globe in relation to the prime meridian.