Resin from his apples (3)
I believe the answer is:
sap
'resin' is the definition.
The definition and answer can be both substances as well as being singular nouns.
Maybe you can see a link between them that I can't see?
'from his apples' is the wordplay.
'from' says the answer is hidden in the clue.
'SAP' can be found hidden inside 'his apples'.
Can you help me to learn more?
(Other definitions for sap that I've seen before include "Watery substance in a plant" , "Weak foolish person" , "trench used in siege" , "Internal tree moisture" , "Fluid in plant stems" .)