Boy band played trumpets on a record (4)
I believe the answer is:
blue
'played trumpets on a record' is the definition.
The answer and definition are different parts of speech. However, adjectives and past participle verbs can occasionally mean the same thing.
'boy band' is the wordplay.
'boy' becomes 'b' (abbreviation used in schools).
'band' becomes 'lue' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'b'+'lue'='BLUE'
Can you help me to learn more?
(Other definitions for blue that I've seen before include "Sky-coloured" , "Sea colour" , "Dismal" , "Colour of depression" , "Vulgar" .)