The pappus of the thistle, by which the achenia are borne by the wind to great distances. See cuts under thistle.(noun)
The Century Dictionary (Public Domain)
Use "thistle-down" in a sentence
"In the Chopiniana scene there is nothing to remind one of the coquetry of the doll in the lovely spirit-like creature who seems to drift on the air like a thistle-down."
"“They are too slight and unsolid pledges, my lord,” said the Queen; “add at least a handful of thistle-down to give them weight in the balance.”"
"The majority of the people are too ignorant to know the value of a book and they regard poetry as the thistle-down of speech."