Clear, all the actors in show (9)
I believe the answer is:
broadcast
'show' is the definition.
(broadcast is a kind of show)
I don't understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for broadcast that I've seen before include "Transmit over airwaves" , "Transmit (programme)" , "Transmission" , "Transmit by radio or TV" , "Send out over the airwaves" .)