Tiny vegetable, and not a whole fruit (3)
I believe the answer is:
pea
'fruit' is the definition.
(pea is a kind of fruit)
I don't understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for pea that I've seen before include "Leguminous seed" , "registered by princess in bed" , "It may climb frame" , "Edible green seed" , "Spherical vegetable" .)