From Longman Dictionary of Contemporary Englishthistledownthis‧tle‧down /ˈθɪsəldaʊn/ noun [uncountable] HBPthe soft feathery substance fastened to thistle seeds that helps them to float in the air
Examples from the Corpus
thistledown• A thistledown floated into the bright phallus of the sunbeam and hovered over his face.• He blew a bit of thistledown from the still-wet surface of his picture.• She was no lightweight, yet he had lifted her as though she were thistledown. 