Final word mine in each pub (7)
I believe the answer is:
epitaph
'final word' is the definition.
The definition and answer can be both related to communication as well as being singular nouns.
Perhaps they are linked in a way I don't understand?
'mine in each pub' is the wordplay.
'mine' becomes 'pit' (down the pit).
'in' means one lot of letters goes inside another.
'each' becomes 'ea' (abbreviation).
'pub' becomes 'ph' (abbreviation).
'pit' placed into 'ea' is 'epita'.
'epita'+'ph'='EPITAPH'
Can you help me to learn more?
(Other definitions for epitaph that I've seen before include "Words inscribed on tombstone." , "Gravestone message" , "Commemorative inscription" , "message celebrating memories?" , "Statement of commemoration for a dead person" .)