On the allotment, one on both sides? (5)
I believe the answer is:
onion
'one on both sides?' is the definition.
Although both the answer and definition are singular nouns, I cannot understand how they can define each other.
'on the allotment' is the wordplay.
'the allotment' becomes 'ion' (I can't explain this - if you can you should give a lot more credence to this answer).
'on'+'ion'='ONION'
Can you help me to learn more?
(Other definitions for onion that I've seen before include "Type of allium" , "Plant with edible bulb" , "veggie" , "Bulb used as a vegetable" , "Pungent vegetable" .)