Iconify the selected Emacs frame (iconify-or-deiconify-frame). The normal meaning of C-z, to suspend Emacs, is not useful under a window system, so it has a different binding in that case.

If you type this command on an Emacs frame's icon, it deiconifies the frame.

Delete the selected frame (delete-frame). This is not allowed if there is only one frame.

Select another frame, raise it, and warp the mouse to it so that it stays selected. If you repeat this command, it cycles through all the frames on your terminal.