Granny Smith, for one
I believe the answer is:
apple
'granny smith for one' is the definition.
(granny smith is a kind of apple)
This is all the clue.
(Other definitions for apple that I've seen before include "eg Cox, Bramley" , "Pipped fruit" , "Jonathan, for example" , "Eg, Bramley, Braeburn" , "Fruit of the rose family" .)