Is a cross connection when two dissimilar piping materials are joined or when plumbing and electrical systems mix?

Is a cross connection when two dissimilar piping materials are joined or when plumbing and electrical systems mix?
A cross connection in plumbing occurs when in two dissimilar sections are connected to together, such as the hot and cold or pump and city water. When plumbing and electricity are connected we just call that:dangerous .
Regards, Tom