Bounce

1. A description of what occurs when an e-mail message has been returned back to the sender as undeliverable. Some e-mail programs also have a bounce feature built into the program that allows the user to easily bounce a message back to the sender making that sender believe the e-mail address is no longer valid. Bounce messages allow the sender of an e-mail address to know that the mail was not successfully delivered.
2. A term sometimes used to describe a computer that has been rebooted.

Also see: E-mail, Reboot