mailbag

noun

1. A strong canvas bag used for the transportation of mail.

   “The communicating doors of adjoining vehicles are opened simultaneously by pressing a large push-button located a suitable height for a man loaded with mailbags to contact it with his shoulder; after a time-lag of seven seconds the doors close automatically.”

2. A smaller bag, slung from the shoulder, used by a mail carrier during the delivery of mail.
3. (broadly, figuratively)The correspondence received by a publishing entity such as a magazine or website.

   “In our mailbag this month, we've got no less than 12 letters from those of you who think that Jones should not have been benched.”