Said to be part of a revolver (5)
I believe the answer is:
spoke
This clue could be a double definition.
'said' is the first definition.
The answer and definition can be both to do with communicating as well as being past participle verbs.
Perhaps you can see an association between them that I don't see?
'part of a revolver' is the second definition.
The answer and definition can be both man-made objects as well as being singular nouns.
Perhaps there's a link between them I don't understand?
'to be' is the link.
Can you help me to learn more?
(Other definitions for spoke that I've seen before include "biker's bar" , "Radiating rod" , "Talked" , "gave a lecture" , "Radius" .)