What does "gilthead" mean?

Gilthead: A marine fish. The name is applied to two species: (a) The Pagrus, or Chrysophrys, auratus, a valuable food fish common in the Mediterranean (so named from its golden-colored head); -- called also giltpoll. (b) The Crenilabrus melops, of the British coasts; -- called also golden maid, conner, sea partridge.