Interface and UML / patterns

I'm preparing an oral presentation of the subject Interface in 'Software Construction'.

One of the keywords it's recomended I talk about are "UML - Use in Design - Patterns - Use in ADT".

All I can think of (or know of) is to show a hierachy of an interface as a superclass and show a "is-a" relationship between the superclass and the subclasses (in a diagram).

I'm not looking for answers, just a little help on how to deal with these keywords. What does Interface has to do with these patterns?