An Etymological Dictionary of the German Language/hell
hell, adj., ‘clear, bright, evident,’ from MidHG. hël (gen. hëlles), adj., ‘loud, sonorous,’ OHG. hël in gahël, unhël, missahëll; in MidHG. the meaning ‘sonorous’ was still current, but that of ‘glittering’ is found neither in OHG. nor MidHG. Comp. OHG. hëllan, MidHG. hëllen, ‘to resound’; MidHG. hal (gen. halles), m., ‘sound, resonance,’ whence ModHG. hallen; further Scand. hjal, n., ‘chattering,’ hjala, ‘to chatter’?. Comp. holen.