wm state

wm state window ?newstate?

If newstate is specified, the window will be set to the new state, otherwise it returns the current state of window: either normal, iconic, withdrawn, icon, or (Windows only) zoomed. The difference between iconic and icon is that iconic refers to a window that has been iconified (e.g., with the wm iconify command) while icon refers to a window whose only purpose is to serve as the icon for some other window (via the wm iconwindow command). The icon state cannot be set by this command.