from
The Collaborative International Dictionary of English v.0.48
Nereid \Ne"re*id\, n.; pl. E. {Nereids}, L. {Nereides}. [L.
Nereis, -idis, Gr. Nhrei:`s Nhrhi:`s, Nhrhi:`dos, a daughter
of Nereus, a nymph of the sea, fr. Nhrey`s Nereus, an ancient
sea god; akin to nhro`s wet, Skr. n[=a]ra water, cf. Gr.
na`ein to flow.]
1. (Class. Myth.) A sea nymph, one of the daughters of
Nereus, who were attendants upon Neptune, and were
represented as riding on sea horses, sometimes with the
human form entire, and sometimes with the tail of a fish.
[1913 Webster]
2. (Zool.) Any species of {Nereis}. The word is sometimes
used for similar annelids of other families.
[1913 Webster]