Showing some turn of pace, it's topping (3)
I believe the answer is:
cap
'showing' is the definition.
The answer and definition can be both related to communication as well as being singular nouns.
Perhaps they are linked in a way I don't understand?
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for cap that I've seen before include "'If the . . . fits, wear it' (3" , "Peaked hat" , "Soft headgear" , "Surpass with headwear" , "Stopper" .)