Category:Hypoptilum

Hy*pop"ti*lum, n.; pl. L. Hypoptila, E. Hypoptilums. Etym: [NL., fr. Gr. (Zoöl.)

Defn: An accessory plume arising from the posterior side of the stem of the contour feathers of many birds; -- called also aftershaft. See Illust. of Feather.