The voice is carrying one right back (5)
I believe the answer is:
tenor
'the voice' is the definition.
(one of the voices in a choir say)
'carrying one right back' is the wordplay.
'carrying' means one lot of letters goes inside another.
'right' becomes 'rt' (abbreviation as in Rt Hon- the Right Honourable).
'back' shows that the letters should be reversed in order.
'one' going within 'rt' is 'ronet'.
'ronet' in reverse letter order is 'TENOR'.
'is' is the link.
(Other definitions for tenor that I've seen before include "Pavarotti, maybe" , "High male singing voice like Pavarotti" , "intent" , "Meaning - male singing voice" , "Placido Domingo, say" .)