DOWN, a smooth rounded hill, or more particularly an expanse of high rolling ground bare of trees. The word comes from the Old English dún, hill. This is usually taken to be a Celtic word. The Gaelic and Irish dun and Welsh din are specifically used of a hill-fortress, and thus frequently appear in place-names, e.g. Dumbarton, Dunkeld, and in the Latinized termination - dunum, e.g. Lugdunum, Lyons. The Old Dutch duna, which is the same word, was applied to the drifted sandhills which are a prevailing feature of the south-eastern coast of the North Sea (Denmark and the Low Countries), and the derivatives, Ger. Düne, modern Dutch duin, Fr. dune, have this particular meaning. The English "dune" is directly taken from the French. The low sandy tracts north and south of Yarmouth, Norfolk, are known as the "Dunes," which may be a corruption of the Dutch or French words. From "down," hill, comes the adverb "down," from above, in the earlier form "adown," i.e. off the hill. The word for the soft under plumage of birds is entirely different, and comes from the Old Norwegian dun, cf. ædar-dun, eider-down. For the system of chalk hills in England known as "The Downs" see Downs.
Note - this article incorporates content from Encyclopaedia Britannica, Eleventh Edition, (1910-1911)