1. [common; perhaps by analogy to a bouncing check] An electronic mail message that is undeliverable and returns an error notification to the sender is said to bounce. See also bounce message.
2. To engage in sexual intercourse; prob.: from the expression ‘bouncing the mattress’, but influenced by Roo's psychosexually loaded “Try bouncing me, Tigger!” from the Winnie-the-Pooh books. Compare boink.
3. To casually reboot a system in order to clear up a transient problem (possibly editing a configuration file in the process, if it is one that is only re-read at boot time). Reported primarily among VMS and Unix users.
4. [VM/CMS programmers] Automatic warm-start of a machine after an error. “I logged on this morning and found it had bounced 7 times during the night”
6. [IBM] To power cycle a peripheral in order to reset it.