Upsets everyone in bar in foreign capital (6)
I believe the answer is:
dollar
'foreign capital' is the definition.
The definition and answer can be both related to communication as well as being singular nouns.
Perhaps there's a link between them I don't understand?
'upsets everyone in bar' is the wordplay.
'upsets' says the letters should be written backwards.
'everyone' becomes 'all' (I've seen this before).
'in' indicates putting letters inside.
'bar' becomes 'rod' (I've seen this before**).
'all' going inside 'rod' is 'rallod'.
'rallod' in reverse letter order is 'DOLLAR'.
'in' is the link.
Can you help me to learn more?
(Other definitions for dollar that I've seen before include "Standard monetary unit of many countries" , "One hundred cents" , "Foreign currency" , "Australian currency" , "American currency" .)