Adage Rod composed in book fit for composting (13)
I believe the answer is:
biodegradable
'fit for composting' is the definition.
I can't tell whether this defines the answer.
'adage rod composed in book' is the wordplay.
'composed' indicates anagramming the letters.
'in' is an insertion indicator.
'book' becomes 'bible' (bible is a kind of book).
'adage'+'rod'='adagerod'
'adagerod' with letters rearranged gives 'odegrada'.
'odegrada' going inside 'bible' is 'BIODEGRADABLE'.
Can you help me to learn more?
(Other definitions for biodegradable that I've seen before include "Capable of being decomposed" , "Eco-friendly" , "Naturally breaking down" , "Able to be broken down by bacteria" .)