Mark’s broadcast (6)
I believe the answer is:
splash
This clue could be a double definition.
'mark's' is the first definition.
(thesaurus)
'broadcast' is the second definition.
Although both the answer and definition are singular nouns, I can't see how one could define the other.
Can you help me to learn more?
(Other definitions for splash that I've seen before include "Sound of dive" , "Small amount of soda water etc" , "Effect of fall into water" , "coming down of an astronaut" , "sensation" .)