(Γράνικος), a river god of Mysia, is described by Hesiod (Hes. Th. 342) as a son of Oceanus and Thetys. But according to Stephanus Byzantinus (s. v. Γραικός), the name Granicus was derived by some from Graecus, the son of Thessalus.
[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