An Etymological Dictionary of the German Language/Annotated/Tümpel

Tümpel, masculine, ‘pool, deep part of a lake’; a Middle German form for Middle High German tümpfel, ‘deep place in flowing or standing water, pool, puddle,’ Old High German tumfilo, masculine, ‘whirlpool’ (whence the equivalent Italian tonfano). A derivative of the nasalized root dup, ‘to be deep’ (see taufen, tief), which appears also in English dimple, Dutch dompelen, ‘to dive, plunge,’ dompelaar, ‘diver’ (bird). Pre-Teutonic dhumb, ‘to be deep,’ is also assumed by Lithuanian dumbu, ‘to get hollow.’ Compare also Topf.