Pole crossing a thoroughfare (4)
I believe the answer is:
road
'thoroughfare' is the definition.
(a thoroughfare is a type of road)
'pole crossing a' is the wordplay.
'pole' becomes 'rod' (synonyms).
'crossing' means one lot of letters goes inside another (to cross can mean to go over or around).
'rod' placed around 'a' is 'ROAD'.
(Other definitions for road that I've seen before include "mine gallery" , "public highway" , "motorway?" , "See 2" , "See 10" .)