“Your question is simple, the answer a little complicated, and it sometimes can be controversial.
User Experience Design is an approach to design that considers all aspects of a product or service with the user. That includes the beauty and function: (usability and accessibility) of a product or a flow and things like delight and emotion—things that are harder to engineer and achieve.
While a designer can create a toggle, a flow, or an interaction that is beautiful, unique, sexy, and functional in a flow—UXD extends into all the disciplines that come together to make the user experience as a whole great.
Yes, you have interaction designers, but you also have content strategists, information architects, user researchers, engineers, and product managers—all of whom have a shared responsibility to create an experience that is easy to use and leaves users pleased because it is adding value to them.”