1.mail

You're referring to the postal service!

Here are some common uses of the term "mail":

1. Sending letters or packages: You can send mail to someone by putting a letter or package in an envelope or box and affixing a postage stamp.
2. Email: In the digital age, "mail" can also refer to electronic mail, or email. This is a way to send messages electronically to others.
3. Mailbox: A mailbox is a container where mail is delivered to a person's home or office.
4. Mail carrier: A mail carrier is a person who delivers mail to homes and businesses.

Do you have a specific question about mail or would you like to know more about a particular aspect of it?