Duke of Lancaster, 1340–99,English soldier and statesman: fourth son of Edward III; founder of the royal house of Lancaster (father of Henry IV of England).
mid-15c. (as a surname from mid-13c.), from Middle French gant, of uncertain origin; perhaps from a Scandinavian source (cf. Old Norse gand "a thin stick," also "a tall thin man") and somehow connected with the root of gander. Connection also has been suggested to Old French jaunet "yellowish" [Middle English Dictionary].
