Gristle (9)
I believe the answer is:
cartilage
'gristle' is the definition.
(I know that gristle can be written as cartilage)
This is all the clue.
(Other definitions for cartilage that I've seen before include "bodily tissue" , "Gristle" , "Connective tissue in joints" , "Tough white flexible tissue attached to bones" .)