noun
barb; ramus (of a feather)
Ornithological term for the slender branches extending from the rachis of a feather.
鳥の羽根の羽枝は、顕微鏡で見ると細かい枝分かれをしている。
Under a microscope, the barbs of a bird's feather show fine branching.
noun
pinnule (of a feather)
Zoological term for the secondary branches on a feather barb; less common than the general 'barb' sense.
羽枝のさらに細かい枝を小羽枝と呼ぶ。
The even finer branches of a barb are called barbules (小羽枝).