Reach god by bus, finally (4)
I believe the answer is:
span
'reach' is the definition.
(thesaurus)
'god by bus finally' is the wordplay.
'god' becomes 'pan' (Pan is an example).
'by' says to put letters next to each other.
'finally' says to take the final letters.
The final letter of 'bus' is 's'.
'pan' after 's' is 'SPAN'.
(Other definitions for span that I've seen before include "Extent from end to end or across" , "Team of two matched oxen" , "too short for the foot" , "Hand's width" , "Extent - 23cm" .)