Sound broadcasting organisation (7)
I believe the answer is:
channel
This clue could be a double definition.
'sound' is the first definition.
(synonyms)
'broadcasting organisation' is the second definition.
Although both the answer and definition are singular nouns, I don't see how one could define the other.
Can you help me to learn more?
(Other definitions for channel that I've seen before include "Length of water; radio station" , "Seaway south of England" , "Water passage; TV station" , "Narrow sea" , "Means of passage or communication" .)