a duck, Anas platyrhynchos, common over most of the N hemisphere, the male of which has a dark green head and reddish-brown breast: the ancestor of all domestic breeds of duck
[C14: from Old French mallart, perhaps from maslart (unattested); see male, -ard]
early 14c., "wild drake or duck," from M.L. mallardus, apparently from male, from L. masculus (see male), in which case the original sense was probably not of a specific species but of any male wild duck. The specific sense of "male of the wild duck" was in M.E. (early 14c.).