back pocket

plural back pockets · alternative backpocket · alternative back-pocket

1. A pocket found on the back of a pair of trousers.

   1 more example

   To appear in the know, regale your new Italian chums with tales of how he covered the Italy squad in his Panini stickers album with nothing but his own face, or the classic story of the time he was stopped by police with £5,000 in cash in his backpocket and explained it with the line "Because I am rich".

   2014 June 20, Pete Cashmore, “How to become an instant Italy fan”, in The Guardian