Animal fibre (9)
I believe the answer is:
horsehair
'animal fibre' is the definition.
(I know that horsehair is a type of animal fibre)
This is all the clue.
(Other definitions for horsehair that I've seen before include "Mane or tail fibres" , "substance, stranded" , "upholsterer's material" , "It's used in furniture for padding" , "From Arab perhaps" .)