1. [techspeak] To relinquish a claim (of a process on a multitasking system) for service; to indicate to the scheduler that a process may be deactivated until some given event occurs or a specified time delay elapses.
2. In jargon, used very similarly to v. block; also in sleep on, syn.: with block on. Often used to indicate that the speaker has relinquished a demand for resources until some (possibly unspecified) external event: “They can't get the fix I've been asking for into the next release, so I'm going to sleep on it until the release, then start hassling them again.”