Ticket souvenir (4)
I believe the answer is:
stub
'ticket souvenir' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for stub that I've seen before include "Strike against hard object - one's toe, perhaps" , "Butt of pencil or cigarette" , "Counterfoil of cheque, receipt etc" , "Counterfoil of cheque or butt of cigarette" , "Counterfoil, of a cheque say" .)