Kernels (4)
I believe the answer is:
nuts
'kernels' is the definition.
(I have seen 'Edible kernels ' mean 'nuts' so perhaps 'kernels' could also mean 'nuts')
This is the entire clue.
(Other definitions for nuts that I've seen before include "Barmy (colloq)" , "Bolt securers" , "out to lunch" , "Heads - fans - fruit" , "Mad; seeds" .)