UI

UI is User Interface Design & UX is User Experience Design.  Both elements are crucial to a product and work closely together. But despite their professional relationship, the roles themselves are quite different, referring to very different parts of the process and the design discipline.

Where UX Design is a more analytical and technical field, UI Design is closer to what we refer to as graphic design, though the responsibilities are somewhat more complex.

Let us try to simplify this & understand it with the help of an example:

 A car is a product of multiple designs, architectures, features & functions. It has a steering, brake, accelerator, seats, wheels, etc. These are the parts contributing to the design of the car that makes it appealing to the buyer. It is the first interaction. Similarly, the architecture, the wireframing of the website & the design of the website is the first point of interaction of the user with the site. This is User Interface Design.