South is one of the cardinal directions and is opposite to the north.

By Western convention, the bottom side of a map is south; the southern direction has azimuth or bearing of 180°.

True south is the direction towards the southern end of the axis about which the earth rotates, called the South Pole and located in Antarctica. Magnetic south is the direction towards the south magnetic pole, some distance away from the south geographic pole.

Etymology

The etymology of "south" comes the Old English word suth, related to the Old High German word sund, and perhaps sunne in Old English, with the sense of "the region of the sun" (sun culminates in the south in the northern hemisphere).

"The South" usually refers to "regions or countries lying to the south of a specified or implied point of orientation, especially the southeastern part of the United States"Merriam-Webster Dictionary: http://www.m-w.com, i. e. the Southern United States and mainly the Deep South, in a general historical context. The South is also used for "the developing nations of the world", i. e. the third world: see North-South divide.

Other languages have sometimes more interesting derivations. For example, in Rutul jennet can mean both 'paradise' and 'south', because of the tribe's belief that paradise is located in the south of the Rutuls' lands. In many languages of Mesoamerica, 'south' means also 'down'.