An Etymological Dictionary of the German Language/Annotated/stürzen
stürzen, verb, ‘to hurl, overturn, overthrow, sink, plunge,’ from Middle High German stürzen, Old High German sturzen (from *sturzjan, *sturtjan), weak verb, ‘to hurl, sink, turn, cover by inverting’; corresponding to Dutch storten. Allied probably to English to start (to startle, from Anglo-Saxon steartlian). The early history of the Teutonic root stert (to which Sterz is allied?) cannot be traced further back.