Internet messages (1-4)
(Other definitions for e-mail that I've seen before include "Send a message" , "Online post" , "Electronic epistle" , "Means of communication" , "Correspondence sent via internet" .)
(Other definitions for email that I've seen before include "Internet-borne communication" , "Messages between computer terminals" , "Electronic message" , "Digital message" , "Messages via the internet" .)