
• (n.) 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.
Found on
http://thinkexist.com/dictionary/meaning/hypoptilum/

<ornithology> An accessory plume arising from the posterior side of the stem of the contour feathers of many birds. ... Synonym: aftershaft. ... (04 Mar 1998) ...
Found on
http://www.encyclo.co.uk/local/20973
Hy·pop'ti·lum noun ;
plural Latin
Hypoptila , English
Hypoptilums . [ New Latin , from Greek
'ypo` beneath + ... down.]
(Zoology) An accessory plume arising from the posterior side of the stem of the contour feathers of many birds; -- called also
afte...Found on
http://www.encyclo.co.uk/webster/H/84
No exact match found.