Source : Webster's Revised Unabridged Dictionary (1913)

Dryad \Dry"ad\, n. [L. dryas, pl. dryades, Gr. ?, pl. ?, fr. ?
   oak, tree. See {Tree}.] (Class. Myth.)
   A wood nymph; a nymph whose life was bound up with that of
   her tree.

Source : WordNet®

dryad
     n : a deity or nymph of the woods [syn: {wood nymph}]
     [also: {dryades} (pl)]