Spud listens to brass (5)
I believe the answer is:
'spud' is the definition.
Although both the answer and definition are singular nouns, I don't understand how they can define each other.
'listens to brass' is the wordplay.
'listens to' shows a homophone (sound like) (I've seen 'listen to' mean this).
'brass' becomes 'tuba' (tuba is a kind of brass).
'tuba' sounds like 'TUBER'.
Can you help me to learn more?
(Other definitions for tuber that I've seen before include "or still vegetating?" , "traveller down in London?" , "Type of plant, potato say" , "Eg, dahlia root" , "Underground stem, root" .)