southyoudaoicibaDictYouDict[south 词源字典]
south: [OE] South, together with its relatives German süd, Dutch zuid, Swedish söder, and Danish syd, goes back to a prehistoric Germanic *suntha-. This may have been derived from the base of *sunnōn ‘sun’ – in which case south would mean etymologically ‘region of the sun, side on which the sun appears’. French sud ‘south’ was borrowed from English.
[south etymology, south origin, 英语词源]
south (adv.)youdaoicibaDictYouDict
Old English suð "southward, to the south, southern, in the south," from Proto-Germanic *sunthaz, perhaps literally "sun-side" (cognates: Old Saxon, Old Frisian suth "southward, in the south," Middle Dutch suut, Dutch zuid, German Süden), and related to base of *sunnon "sun" (see sun (v.)). Old French sur, sud (French sud), Spanish sur, sud are loan-words from Germanic, perhaps from Old Norse suðr.

As an adjective from c. 1300; as a noun, "one of the four cardinal points," also "southern region of a country," both late 13c. The Southern states of the U.S. have been collectively called The South since 1779 (in early use this often referred only to Georgia and South Carolina). South country in Britain means the part below the Tweed, in England the part below the Wash, and in Scotland the part below the Forth. South Sea meant "the Mediterranean" (late 14c.) and "the English Channel" (early 15c.) before it came to mean (in plural) "the South Pacific Ocean" (1520s). The nautical coat called a sou'wester (1836) protects the wearer against severe weather, such as a gale out of the southwest.