A bag or wallet.

A bag containing letters to be delivered by post.

The material conveyed by the postal service.

“Don't forget to pick up the mail on your way.”

(ditransitive) To send (a letter, parcel, etc.) through the mail.

(ditransitive) To send by electronic mail.

“Please mail me the spreadsheet by the end of the day.”

To contact (a person) by electronic mail.

“I need to mail my tutor about the deadline.”