Pronunciation: (nā'ad, -ud, nī'-),[key] —n., —pl.-ads, -a•desPronunciation: (-u-dēz").[key] 1. (sometimes cap.)Class. Myth.any of a class of nymphs presiding over rivers and springs.
2. the juvenile form of the dragonfly, damselfly, or mayfly.
3. a female swimmer, esp. an expert one.
4. Bot.a plant of the genus Najas, having narrow leaves and solitary flowers.
5. Entomol.an aquatic nymph.
6. a freshwater mussel.