Onion, or what people do when cutting one back (4)
I believe the answer is:
bulb
This clue could be a double definition.
'onion' is the first definition.
The definition and answer can be both plants as well as being singular nouns.
Maybe they are linked in a way I don't understand?
'what people do when cutting one back' is the second definition.
The definition suggests a singular noun which matches the answer.
'or' acts as a link.
Can you help me to learn more?
(Other definitions for bulb that I've seen before include "shiner" , "Tulip, for example" , "Corm; electric light" , "Reproductive organ in some plants" , "Eg, onion" .)