An Etymological Dictionary of the German Language/Annotated/Süden
Süden, masculine, ‘south’; the strictly High German form is Sund, which survives in the proper names Sundgau, Sundheim, &c.; compare Old High German sundwint, ‘south wind,’ sundarwint (Middle High German sunderwint). Yet the simple form of the word became obsolete at an early period in Upper German (the term used being Mittag), the names of the other cardinal points being also unknown. The loss of the n in Süden (Middle High German sunden. Old High German sundan) points to the adoption of the word from Low German. The primitively Teutonic stem sunþ-, ‘south,’ is also assumed by Old Icelandic sunnan, Anglo-Saxon sûðan, ‘from the south,’ Anglo-Saxon sûð, Dutch zuid, Old Saxon sûth, ‘south.’ The term sunþ-, ‘south,’ is as specifically Teutonic as Norden and Westen. Whether sunþ- is derived from sun-, in Gothic sun-nô, ‘sun,’ and means literally ‘sun-side,’ is not certain (yet note Osten as ‘dawn-side’).