Moon around, having no stereo (4)
I believe the answer is:
mono
'stereo' is the definition.
(thesaurus)
'moon around having no' is the wordplay.
'moon' becomes 'm' (this could be a standard abbreviation which I don't know about).
'around' becomes 'o' (a round letter).
'having no' becomes 'no' (I've seen this in other clues).
'm'+'o'+'no'='MONO'
Can you help me to learn more?
(Other definitions for mono that I've seen before include "Single-speaker sound" , "Single-channel sound" , "Transmitting over one channel" , "Not stereo" .)