Thistledown

Part of speech: noun

Definitions

1. The soft, silky white fluff that surrounds the seeds of a thistle and lets them drift on the wind
2. Fine feathery down attached to thistle seeds, carried far by even the gentlest breeze
3. Light, airy tufts produced by thistle plants that help their seeds scatter across open ground

Etymology: Thistledown is a plain compound: "thistle" joined to "down," the soft fluff that clings to the seeds of thistles. The second element is the more interesting one. "Down" here is not the word for a hill, though the two are related. It comes from Middle English "doun," which entered from Old Norse "dúnn," meaning the soft feathers of birds, and that in turn traces back to a Proto-Germanic root "dūnaz." So the fine plumage that cushions a bird's nest and the silky seed-tufts blown off a thistle share one ancestor. The hill sense came later, through a separate use of the same word. English "down" for an open upland is a different development, and only the feather sense sits behind "thistledown." The compound is therefore a meeting of two words that happen to look alike, one describing soft plumage and one describing high grassland.

Synonyms: thistle fluff, down