down-filled

The compound adjective 'down-filled' is a transparent modern English construction. Its first element, 'down,' has a complex history. While its oldest English meaning relates to hills, the sense of 'soft feathers' entered Middle English from Old Norse dúnn, referring specifically to the plumage of birds. This term became associated with luxury bedding and insulation. The second element, 'filled,' derives from the common Germanic verb 'to fill,' indicating a state of being made full. Combined, the term literally describes an item that has been made full with this specific soft insulating material, directly linking the physical substance to its functional purpose in clothing and bedding.

Structure: down (soft feathers) + filled (made full) - down: From Old English dūn (hill, down). In this context, it refers to the soft, fine feathers, a sense derived from the use of such feathers from the eiderdown duck, named after the Icelandic æðardúnn (eider's down), where dúnn meant "down feather." The connection to "hill" is not directly relevant here; the word for the feathers is a separate, convergent linguistic strand. - filled: From Old English fyllan (to fill), from Proto-Germanic fullijaną, from the root fullaz (full). The past participle form used as an adjective meaning "made full."