Bill in American court (3)
I believe the answer is:
act
'bill' is the definition.
(I've seen this in other clues)
'american court' is the wordplay.
'american' becomes 'a' (common abbreviation - e.g. in organisation names).
'court' becomes 'ct' (abbreviation used in road names).
'a'+'ct'='ACT'
'in' is the link.
(Other definitions for act that I've seen before include "Accomplishment" , "Subdivision of a play" , "performing group" , "Perform theatrically" , "law passed" .)