mailer

Noun

 * 1) One who sends mail.
 * 2) A computer program that sends electronic mail.
 * 3) A packet or container designed for postal use.
 * The cassette came in a brown paper mailer.
 * 1) A mailshot; advertising sent by mail.
 * 1) A mailshot; advertising sent by mail.

Etymology
From.

Verb

 * 1) to email send an email