Quiz: Remember the definition of mal de mer?
"Gods of the Lower World," in Roman religion, from Latin manes "departed spirit, ghost, shade of the dead, deified spirits of the underworld," usually said to be from Latin manus "good," thus properly "the good gods," a euphemistic word, but Tucker suggests a possible connection instead to macer, thus "the thin or unsubstantial ones."
Old English manu "mane," from Proto-Germanic *mano (cf. Old Norse mön, Old Frisian mana, Middle Dutch mane, Dutch manen, Old High German mana, German Mähne "mane"), from PIE *mon- "neck, nape of the neck" (cf. Sanskrit manya "nape of the neck," Old English mene "necklace," Latin monile "necklace," Welsh mwng "mane," Old Church Slavonic monisto, Old Irish muin "neck").