powder down

名词 n.
中文释义

英文释义

名词 n.
  1. A special type of down that occurs in a few groups of apparently unrelated birds. In some species, the tips of the barbules on the feathers disintegrate, forming fine particles of keratin; in others, powder grains come from cells that surround the barbules of growing feathers. uncountable
    — All parrots have powder down.
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