Hypoptilum
Pronunciation : Hy*pop"ti*lum, n.; pl. L. Hypoptila
Part of Speech : E.
Etymology : [NL., fr. Gr. (Zo?l.)
Definition : 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.
Hypoptilums.
Source : Webster's Unabridged Dictionary, 1913