Telephone round (4)
I believe the answer is:
ring
I believe this clue is a double definition.
'telephone' is the first definition.
('ring' can be a synonym of 'telephone')
'round' is the second definition.
('ring' can be a synonym of 'round')
(Other definitions for ring that I've seen before include "Piece of jewellery" , "Besiegers' formation" , "place for fight" , "Arena; jewellery item" , "Dial" .)