If one were to horizontally divide the earth in half at the equator, each half would be a:

The correct answer is - hemisphere.

One of the purposes of the Equator is to divide the Earth into two halves, more commonly known as hemispheres. The Equator is dividing the Earth on North Hemisphere and South Hemisphere. The line of division, or rather the Equator, will be passing through the middle part of Africa, northern part of the Indian Ocean, through the Indonesian Islands, the middle part of the Pacific Ocean, northern part of South America, and through the northern part of the South Atlantic.

The Northern Hemisphere will be a hemisphere where the land is much more abundant, while the Southern Hemisphere will be the one where the ocean waters are by far more dominant than the land.