suspend-frame

suspend-frame is an interactive compiled Lisp function in `frame.el'.

It is bound to C-z, C-x C-z.

(suspend-frame)

Do whatever is right to suspend the current frame.
Calls `suspend-emacs' if invoked from the controlling tty device,
`suspend-tty' from a secondary tty device, and
`iconify-or-deiconify-frame' from an X frame.