The term "invisible light" seems to me a contradiction- "light" pretty much means "visible electromagnetic radiation".
Romsek, correctly, referred to the difference between "light" and "radio waves" as one of frequency. I tend to think of it as a "wave length" (of course, a specific frequency gives a specific wave length). Light has wave length on the order of \(\displaystyle 10^{-7}\) m while radio waves length is on the order of several hundred meters, a "city block" or more.