Raid carried out by old medium (5)
I believe the answer is:
radio
'medium' is the definition.
(I know that radio is a type of broadcasting)
'raid carried out by old' is the wordplay.
I cannot quite understand how this works, but
an anagram of 'raid' is 'radi' which is present in the answer.
'old' could be 'o' (abbreviation as in OT - Old Testament) and 'o' is located in the answer.
This accounts for all the letters.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for radio that I've seen before include "Contact" , "Speech receiver" , "Broadcast medium" , "Sound broadcasting" , "means of communication" .)