One periodically instrumental in public communication? (5)
I believe the answer is:
organ
'one periodically instrumental in public communication?' is the definition.
The answer and definition can be both related to communication as well as being singular nouns.
Maybe there's a link between them I don't understand?
'public communication?' is the wordplay.
'public' becomes 'org' (I can't justify this - if you can you should give a lot more credence to this answer).
'communication?' becomes 'AN' (AN is an example).
'org'+'an'='ORGAN'
Can you help me to learn more?
(Other definitions for organ that I've seen before include "Wind and keyboard instrument" , "Possibly stomach" , "Publication - musical instrument" , "Heart or lung, say" , "Soft part of the body which has a specific function" .)