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. [Stanford] To play volleyball. The now-demolished D. C. Power Lab building used by the Stanford AI Lab in the 1970s had a volleyball court on the front lawn. From 5 P.M. to 7 P.M. was the scheduled maintenance time for the computer, so every afternoon at 5 would come over the intercom the cry: "Now hear this: bounce, bounce!", followed by Brian McCune loudly bouncing a volleyball on the floor outside the offices of known volleyballers. 3. 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. 4. 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. 5. [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.