Definition of the word hemisphere

The word "hemisphere" derives from two Greek words, "hemi" meaning half, and "sphaira" meaning sphere. It was coined by the Flemish cartographer, Gerardus Mercator, in the 16th century to describe the two halves of the globe that can be thought of as separate entities because each half is distinct, with its own topography, climate, and culture. The term was adopted by scientists and scholars to refer to the two halves of the brain, as these two regions were found to have distinct functional capabilities as well. Today, the usage of the word "hemisphere" extends beyond its original geographic connotation to include any symmetrical, half-section of a larger whole, such as the human brain or a cell nucleus.