Widespread issue of currency (5)
I believe the answer is:
delta
This clue could be a double definition.
'widespread issue' is the first definition.
The answer and definition can be both related to communication as well as being singular nouns.
Perhaps there's an association between them I don't understand?
'currency' is the second definition.
Although both the answer and definition are singular nouns, I don't understand how one could define the other.
'of' acts as a link.
Can you help me to learn more?
(Other definitions for delta that I've seen before include "Estuary area where river has split" , "Spreading river mouth" , "Nile river mouth" , "Silted estuary" , "Divided river outlet" .)