Cellulose fabric (5)
I believe the answer is:
'cellulose fabric' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for rayon that I've seen before include "Silklike material" , "Or any (anag) -- fibre" , "Synthetic silk-like fabric" , "Cellulose fabric" , "Viscose fabric" .)