All the money that may be made with apples perhaps (8)
I believe the answer is:
turnover
'money that may be made with apples perhaps' is the definition.
Although both the answer and definition are singular nouns, I don't see how they can define each other.
I don't understand the rest of the clue.
Can you help me to learn more?
(Other definitions for turnover that I've seen before include "Business revenue" , "Total amount of money taken by a business" , "Amount of business - pasty" , "(Annual) money taken by business; small pie" , "The amount of money taken by a business in a particular period" .)