one of the main flight feathers projecting along the outer edge of a bird's wing
例句
用作名词 (n.)
Upperwing has pale greyish-white primary bases and often pale rufous or yellowish-brown forewing, paler than dark grey flight-feathers. 翼上初级飞羽呈现灰白色，翼前缘经常为淡棕色或黄棕色，比飞羽的深灰色要浅。
美
