After the third, this will be left to the journalists, being members (6,6)
I believe the answer is:
fourth estate
'after the third this will be left' is the definition.
The definition and answer can be both related to communication as well as being singular nouns.
Maybe they are linked in a way I don't understand?
'to the journalists being members' is the wordplay.
I cannot quite see how this works, but
'to the' could be 'the' and 'the' is found within the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for fourth estate that I've seen before include "Journalistic profession - press" , "addition to three-car family?" .)