Definition of: naiad

(nā′ad, nī′-) noun plural ·ads or ·a·des (-ə·dēz)
1. In classical mythology, one of the water nymphs who were believed to dwell in and preside over fountains, lakes, brooks, and wells.
2. Bot. A plant of the pondweed family (genus Naias).
3. The nymph stage in the life cycle of certain insects: applied especially to aquatic forms. [<Gk. Naias, -ados. Related to Gk. naein flow.]