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) but still has an entry in the process table. 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, the zombie's entry is removed from the process table and it is said to be "reaped". Unlike the normal processes, zombie processes cannot be removed from a system with the kill command since they are already dead. (This is where the term's metaphor [zombie - an undead person] comes from.) To reap a zombie process, SIGCHLD signal can be sent to the parent process manually using the kill command. If the parent process refuses to reap the zombie, then terminating the parent process (mostly with SIGTERM signal) can be an option. When a child process loses its parent, init process becomes its new parent and it will reap any zombies since it executes the wait system call periodically.