Wiktionary
n. (context computing English) A child process that has terminated but is still listed in the process table, having not yet been reaped by its parent process.
Wikipedia
On Unix and Unix-like computer operating systems, a zombie process or defunct process is a process that has completed execution (via the [[exit (system call)|exit]] system call) but still has an entry in the process table: it is a process in the " Terminated state". This occurs for child processes, where the entry is still needed to allow the parent process to read its child's exit status: once the exit status is read via the [[wait (system call)|wait]] system call, the zombie's entry is removed from the process table and it is said to be "reaped". A child process always first becomes a zombie before being removed from the resource table. In most cases, under normal system operation zombies are immediately waited on by their parent and then reaped by the system – processes that stay zombies for a long time are generally an error and cause a resource leak.
The term zombie process derives from the common definition of zombie — an undead person. In the term's metaphor, the child process has "died" but has not yet been " reaped". Also, unlike normal processes, the [[kill (command)|kill]] command has no effect on a zombie process.
Zombie processes should not be confused with orphan processes: an orphan process is a process that is still executing, but whose parent has died. These do not remain as zombie processes; instead, (like all orphaned processes) they are adopted by [[init]] (process ID 1), which waits on its children. The result is that a process that is both a zombie and an orphan will be reaped automatically.
Usage examples of "zombie process".
Even her dress was whole now, apparently renovating itself as part of the zombie process.
Something in the zombie process had destroyed their sight and much of their hearing, so that they were largely dependent on tactile input.