A list of
e-mail addresses identified by a single name, such as
mail-list@sandybay.com. When an
e-mail message is sent to the mailing list name, it is automatically forwarded to all the addresses in the list.
Most e-mail clients support mailing lists, which enables you to broadcast e-mail messages to groups that you define. In addition, there are mailing list servers that manage centralized mailing lists for groups of users.
Also see Why E-Mails Bounce in the Did You Know section of Webopedia.