Πλάγκος, the name of the most distinguished family of the plebeian Munatia gens, is said to have signified a person having flat splay feet without any bend in them. (Plin. Nat. 11.4.5. s. 105; Festus, s. v. Planeae.) Instead of Plancus we frequently find Plancius both in manuscripts and editions of the ancient writers. For a detailed account of the persons mentioned below, see Drumann's Rom. vol. iv. p. 205, &c.
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