An Etymological Dictionary of the German Language/Mähne
Mähne, f., ‘mane,’ earlier ModHG. also Mane (the mutation, which also occurs in Suab. and Bav., seems to be due to the plur.), from the equiv. MidHG. mane, man, f. and m., OHG. mana, f.; comp. Du. maan, AS. manu, E. mane, OIc. mǫn, f., ‘mane’ (to this is allied the derivative OIc. makke, Swed. and Dan. manke, ‘upper part of the neck of a horse’). The common Teut. manô, f., ‘mane’ (Goth. *mana, f., is by chance not recorded), shows a later development of meaning, for the earlier sense of the word was certainly ‘neck’ merely; in OTeut. occurs a derivative signifying ‘necklace’; comp. OIc. men, AS. męne, OSax. męni, OHG. męnni, n., ‘necklace.’ To these are allied, in the non-Teut. languages, Lat. monile, ‘necklace, collar,’ Dor. μάννος, μάνος, μόννος, ‘necklace,’ Kelt. μανιάκης, equiv. to OIr. muince, ‘necklace,’ Sans. mani, m., ‘string of pearls.’ An OInd. *manâ, f., ‘neck,’ is wanting, though manyâ, f., ‘nape,’ occurs. Further, OIr. muin, muinél, ‘nape,’ mong, ‘hair, mane,’ with which Swed. and Dan. manke, mentioned above, is closely connected.