zombie and orphan

I don't understand UNIX-like operating system sometimes. I assume that a parent spawn a child process, then if the child process dies, but the parents have not reaped it, then that child process is named a zombie. If the parent dies, the child becomes an orphan, taken over by the init.

Firefox starts a netstat, which is a zombie until I close firefox.

The six basic ideas are fork, exec, open, close, read, and write. Hmm.