Number disembarking from rear American vehicle (3)
I believe the answer is:
bus
'american vehicle' is the definition.
'bus' can be an answer for 'vehicle' (public transport vehicle). I'm unsure of the 'american' bit.
'number disembarking from rear' is the wordplay.
'number' becomes 'n' (n can represent any number).
'disembarking from' is a deletion indicator.
'rear' becomes 'buns' (synonyms).
'buns' with 'n' removed is 'BUS'.
Can you help me to learn more?
(Other definitions for bus that I've seen before include "Coach" , "eg Double-decker" , "Public service vehicle" , "Public transport vehicle" , "Charabanc" .)