[ 'ʃɛldʌk ]
■ noun ( plural same or ~s ) a large goose-like duck with boldly marked plumage. [ Tadorna tadorna and related species.]
Origin
C18: prob. from dialect sheld 'pied' (rel. to MDu. schillede 'variegated') + duck 1 ; the term sheldrake (sometimes used for the male) dates from ME.