An Etymological Dictionary of the German Language/Schwaden

by Friedrich Kluge

Schwaden, Schwadem, m., ‘vapour, damp, exhalation,’ from MidHG. swadem, swaden, m., ‘vapour’; allied to North Fris. swesh, AS. swaðul, m., ‘smoky vapour,’ OHG. swëdan, ‘to burn slowly with a smoky flame.’ The Teut. root sweþ contained in these words seems to correspond to the root sū̆þ contained in sieden (comp. suk, swak, under the preceding word; see toll).