One part of an animal that's vegetable (7)
I believe the answer is:
cowslip
'one part of an' is the definition.
Although both the answer and definition are singular nouns, I can't understand how they can define each other.
'animal that's vegetable' is the wordplay.
I cannot quite see how this works, but
'animal' could be 'cow' (cow is a kind of animal) and 'cow' is located in the answer.
The remaining letters 'slip' is a valid word which might be clued in a way I don't understand.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for cowslip that I've seen before include "Flowering plant" , "Early spring flower" , "Plant with yellow flower" , "Type of primrose" , "Yellow field flower" .)