afterfeather
/ˈɑːftəˌfɛðə/ /ˈaftəˌfɛðə/Ornithology
noun
A secondary structure attached to the undersurface of the shaft of a contour feather, typically resembling a smaller and downier feather; also called hyporachis.
Origin
1930s; earliest use found in Science. From after- + feather.