What is the difference between UI Design and UX Design?

UX design deals with the overall experience associated with the use of a product or service.

[b]UI design[/b] deals with the specific user interface(s) of a product or service. The UI can be a component of UX, but many user experiences don't have UIs. The design of a UI will be heavily informed by the UX design. The UX design will be less informed by the UI.