An Etymological Dictionary of the German Language/regen

by Friedrich Kluge

regen, vb., ‘to stir up, move, excite,’ from MidHG. ręgen, ‘to cause to project, set up, excite, move, awaken,’ a factitive of MidHG. rëgen, ‘to rise, tower,’ hence primit. allied to ragen. Akin also to MidHG. rœhe, ‘rigid, stiff.’ The Teut. root rag, rē̆h, of these cognates has not yet been found in the allied languages. See rege.