"Cognate with" means that both are derived from the same source.

That was what my one of German profs told me, but some quick work with Google after reading your post says otherwise. Both English & German etymological sources trace "ghetto" back to an Italian word meaning "to cast", which in turn was derived from Latin iactare, and neither draw any connection to the German Jüden.

Where else can you learn about Italian etymology & UIG's in the same thread?