An Etymological Dictionary of the German Language/hehlen
hehlen, vb. from the equiv. MidHG. hëln, OHG. hëlan, ‘to keep secret, conceal,’ AS. hëlan, E. to heal, ‘to cover, conceal,’ Du. helen, ‘to conceal.’ Root hē̆l, from pre-Teut. kē̆l (Sans. *çal), in the sense of ‘concealing cover’; see further under Halle, Hehl, Hölle, Hülle, Hülse, as well as hohl, Höhle, and Helm. The Aryan root is attested by Lat. cêlare (ê as in Goth. *hêlei, which is indicated by MidHG. hœle, f., mentioned under Hehl), occulo, Gr. root καλ in καλύπτω, ‘I cover,’ καλύβη, ‘hut,’ OIr. celim, ‘I hide.’