Down. The fine, soft covering of fowls under the feathers, particularly that of swans, ducks, geese, and other water-fowls. Down-feathers are characterized by a downy structure throughout. They more or less completely cover the body of the fowl, but are always hidden beneath the contour feathers, and serve as a sort of padding about the bases of the latter. The eider duck yields most of the down of commerce. [See Eiderdown]