Na"iad (?), n. [L. naias, -adis, nais, -idis, a water nymph, Gr , , fr. to flow: cf. F. naiade. Cf. Naid.]
1. Myth.
A water nymph; one of the lower female divinities, fabled to preside over some body of fresh water, as a lake, river, brook, or fountain.
2. Zool.
Any species of a tribe (Naiades) of freshwater bivalves, including Unio, Anodonta, and numerous allied genera; a river mussel.
3. Zool
One of a group of butterflies. See Nymph.
4. Bot.
Any plant of the order Naiadaceae, such as eelgrass, pondweed, etc.
© Webster 1913.