It's useful for sending messages or aid around (5)

I believe the answer is:

radio

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'it's useful for sending messages' is the definition.
I can't judge whether this defines the answer.

'or aid around' is the wordplay.
'around' indicates anagramming the letters.
'or'+'aid'='oraid'
'oraid' with letters rearranged gives 'RADIO'.

Can you help me to learn more?

(Other definitions for radio that I've seen before include "Electronic receiver" , "Sound broadcasting" , "broadcasting station" , "Wireless broadcast" , "MW, LW or FM sound source" .)

I've seen this clue in the Evening Standard.

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