Hypoptilum

1 definition found

From The Collaborative International Dictionary of English v.0.48 [gcide]:

  Hypoptilum \Hy*pop"ti*lum\, n.; pl. L. {Hypoptila}, E.
     {Hypoptilums}. [NL., fr. Gr. "ypo` beneath + ? down.] (Zool.)
     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}.
     [1913 Webster]