barbule

1 9.5

A tiny thread on a bird's feather that links barbs to hold the feather together

noun
/ˈbɑːr.bjuːl/

Specialized

: barbula

Its parts are: 1. Vane 2. Rachis 3. Barbs (connected by barbules and hooks) 4. Afterfeather 5. Calamus.

Examples

Each feather's barbules play a crucial role in maintaining its overall shape and insulation.
And if we look at this one here, we see the barbule and you can see this little hooked regions there.
On either side are branches, barbs... which branch into barbules... which have little barbicels with hooks on the end of them.

Birdy (1984)
Under a microscope, the tiny barbules can be seen branching out from the larger barbs of the feather.
The structure of the feather relies on the presence of barbules that interlock with one another.

Surface Forms

barbule singular

barbules plural

Morphology

barbule = barb (semi-transparent) = barb + ule

The word is formed by 'barb' + the diminutive suffix '-ule'; the meaning 'small barb' is clear in form but the suffix '-ule' is less familiar to many learners.

Etymology

The word barbule comes from the Latin barba meaning 'beard' with a small ending, so it means 'little beard' and makes you imagine tiny beard-like threads on a feather. These tiny threads help the feather's barbs lock together, so barbule names the small parts that keep a feather smooth and help a bird fly.