(Γραῖαι), that is, " the old women." were daughters of Phorcys and Ceto. They had grey hair from their birth. Hesiod (Hes. Th. 270, &c.) mentions only two Graeae, viz. Pephredo and Enyo; Apollodorus (2.4.2) adds Deino as a third, and Aeschylus (Prom. 819) also speaks of three Graeae. The Scholiast on Aeschylus (Prom. 793) describes the Graeae, or Phorcides, as he calls them, as having the figure of swans, and he says that the three sisters had only one tooth and one eye in common, which they borrowed from one another when they wanted them. It is conmmonly believed that the Graeae, like other members of the family of Phorcys, were marine divinities, and personifications of the white foam seen on the waves of the sea. (Comp. GORGO and PERSEUS.)
[L.S]A Dictionary of Greek and Roman biography and mythology
Smith, William
A Dictionary of Greek and Roman biography and mythology. William Smith, LLD, ed. 1890