An Etymological Dictionary of the German Language/Annotated/turnen

by Friedrich Kluge

turnen, verb, ‘to practise gymnastics,’ Modern High German only; no corresponding word is found in Middle High German, which has only turnei, ‘tournament,’ turnieren, ‘to hold a tournament, tilt,’ borrowed from French. The Modern High German word is probably derived from French tourner, ‘to turn, turn round.’