An Etymological Dictionary of the German Language/stürzen
stürzen, vb., ‘to hurl, overturn, overthrow, sink, plunge,’ from MidHG. stürzen, OHG. sturzen (from *sturzjan, *sturtjan), wk. vb., ‘to hurl, sink, turn, cover by inverting’; corresponding to Du. storten. Allied probably to E. to start (to startle, from AS. steartlian). The early history of the Teut. root stert (to which Sterz is allied?) cannot be traced further back.