Interface can be quite confusing for some people, especially when the explanation is made with different technical jargons as well. Try listening to a geeks only discussion about Interfaces, Polyphormism, Inheritance and the like and I'm sure you'll be thrown with plenty of big technical words.
I've written a quick explanation of what an Interface is based on layman language, so if there's a time when your non-techn boss asks you what and why you need an interface, you won't be caught off-guard.