Letters and such (4)
'letters and such' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for mail that I've seen before include "Letters and parcels" , "protective cover" , "Paper" , "Send message" , "Flexible armour" .)
(Other definitions for snail mail that I've seen before include "Conventional (slow) post (informal)" , "Slow delivery" , "Ordinary post" , "traditional post" , "The conventional postal service" .)