The horsey set on the edges of commuter belt (4)
I believe the answer is:
colt
'edges of commuter belt' is the definition.
Although both the answer and definition are singular nouns, I don't see how they can define each other.
'the horsey set on' is the wordplay.
'the' becomes 't' (the is pronounced as a 't' sound in some dialects).
'horsey set' becomes 'col' (I can't explain this - if you can you should give a lot more credence to this answer).
'on' is a charade indicator (letters next to each other).
't' put after 'col' is 'COLT'.
'the' is the link.
Can you help me to learn more?
(Other definitions for colt that I've seen before include "Young player" , "Type of revolver and a young horse" , "Mount" , "Male pony" , "H [HORSE]" .)