Mermaid, masculine merman, a fabled marine creature with the head and upper body of a human being and the tail of a fish. Similar divine or semidivine beings appear in ancient mythologies (e.g., the Chaldean sea god Ea, or Oannes). In European folklore, mermaids (sometimes called sirens) and mermen were natural beings who, like fairies, had magical and prophetic … More Mermaids