(n.) A marine deity; a fabulous being supposed to live in, or have dominion over, the sea, or some particular sea or part of the sea, as Neptune.

Davy Dylan Neptune Nereid Nereus Oceanid Oceanus Poseidon Thetis Triton Varuna fresh-water nymph kelpie limniad man fish mermaid merman naiad nix nixie ocean nymph sea devil sea god sea nymph sea-maid sea-maiden seaman siren undine water god water spirit water sprite