An Etymological Dictionary of the German Language/Annotated/Schwaden

by Friedrich Kluge

Schwaden, Schwadem, masculine, ‘vapour, damp, exhalation,’ from Middle High German swadem, swaden, masculine, ‘vapour’; allied to North Frisian swesh, Anglo-Saxon swaðul, masculine, ‘smoky vapour,’ Old High German swëdan, ‘to burn slowly with a smoky flame.’ The Teutonic root sweþ contained in these words seems to correspond to the root sū̆þ contained in sieden (compare suk, swak, under the preceding word; see toll).