What is the Applescript command to show or hide iTerm2 window

Here are several options (none of them have been tested, so test and see which one works for you):

Option 1:

tell application "iTerm2" to activate
tell application "System Events" to tell process "iTerm2" to keystroke "h" using command down

Note: Keystroke may be replaced with m if you want iTerm2 to be minimized to the dock with the Genie effect.

Option 2:

tell application "Finder"
set visible of process "iTerm2" to false
end tell 

Option 3:

tell application "System Events" to tell process "iTerm2" to set visible to false

Note: The process name may just be iTerm instead of iTerm2. I opened iTerm on my Mac and then Activity Monitor, and the Process Name that it shows is iTerm. Please change accordingly if it does not work for you.

Links and Resources

Here is a great WikiBooks link that describes exactly what you need.

Please let me know which option works for you so I can edit the question and only include the option that works.

Edit:

If you make the iTerm window the frontmost application (Be careful you don't want to make the AppleScript window the frontmost application), try this script:

tell application "System Events"
    set frontProcess to first process whose frontmost is true
    set visible of frontProcess to false
end tell

tell application "System Events" to tell (process 1 where frontmost is true)
    if name is "iTerm" then
        set visible to false
        return
    end if
end tell
tell application "iTerm"
    reopen -- open a default window if there are no open windows
    activate -- make frontmost
end tell

If others were looking for a way to show or hide iTerm in general, you can set a shortcut for it in the preferences or use Alfred: