To suspend a process in such a way that it can be continued. A process may be directly frozen by an explicit request of its superior process or indirectly frozen because its superior has been frozen.

• 挂起一个进程的执行，需要时可以再继续的处理动作，一个进程可以被其上级进程的一个明确的请求直接冻结，也可以因其上级进程已被冻结而冻结。