An Etymological Dictionary of the German Language/Annotated/stöhnen
stöhnen, verb, ‘to groan,’ Modern High German only, property a Low German word. Compare the equivalent Dutch stenen, Anglo-Saxon stunian, Old Icelandic stynja. The verbal root sten, ‘to groan,’ is common to Teutonic; compare Sanscrit stan, ‘to rustle, roar,’ Greek στένω, ‘to groan, roar,’ Old Slovenian stenją, ‘to groan.’ The root sten is a variant of the Aryan root ten, discussed under donnern.