mailbox

A mailbox is like a folder, used to store and organise email messages. Each email account you use in Mail has a set of standard mailboxes — for example, Inbox, Sent, Drafts and Bin. The Mail sidebar shows the mailboxes for each account, as well as mailboxes you create. To show the sidebar, choose View > Show Mailbox List, or press Shift-Command-M.

Mailboxes on your Mac are local, meaning you can access them only on your Mac; they’re shown in the On My Mac section of the Mail sidebar. Mailboxes on an account’s mail server can be accessed on any computer where you use the account; they’re shown in the account section of the sidebar.