Characteristic to employ poles for crossing (7)
I believe the answer is:
transit
'crossing' is the definition.
(thesaurus)
'characteristic to employ poles' is the wordplay.
'characteristic' becomes 'trait' (I've seen this before).
'to employ' indicates putting letters inside.
'poles' becomes 'ns' (North and South poles).
'trait' placed around 'ns' is 'TRANSIT'.
'for' acts as a link.
(Other definitions for transit that I've seen before include "In - - (en route)" , "carriage" , "Pass through; van" , "Pass across/through" , "Conveyance of goods or people - tin star (anag)" .)