An Etymological Dictionary of the German Language/Annotated/Mähne
Mähne, feminine, ‘mane,’ earlier Modern High German also Mane (the mutation, which also occurs in Suabian and Bavarian, seems to be due to the plural), from the equivalent Middle High German mane, man, feminine and masculine, Old High German mana, feminine; compare Dutch maan, Anglo-Saxon manu, English mane, Old Icelandic mǫn, feminine, ‘mane’ (to this is allied the derivative Old Icelandic makke, Swedish and Danish manke, ‘upper part of the neck of a horse’). The common Teutonic manô, feminine, ‘mane’ (Gothic *mana, feminine, is by chance not recorded), shows a later development of meaning, for the earlier sense of the word was certainly ‘neck’ merely; in Old Teutonic occurs a derivative signifying ‘necklace’; compare Old Icelandic men, Anglo-Saxon męne, Old Saxon męni, Old High German męnni, neuter, ‘necklace.’ To these are allied, in the non-Teutonic languages, Latin monile, ‘necklace, collar,’ Doric μάννος, μάνος, μόννος, ‘necklace,’ Keltic μανιάκης, equivalent to Old Irish muince, ‘necklace,’ Sanscrit mani, masculine, ‘string of pearls.’ An Old Indian *manâ, feminine, ‘neck,’ is wanting, though manyâ, feminine, ‘nape,’ occurs. Further, Old Irish muin, muinél, ‘nape,’ mong, ‘hair, mane,’ with which Swedish and Danish manke, mentioned above, is closely connected.