What Does User Interface Design (UI Design) Mean?

User interface design (UI design) refers to the design of various types of software and hardware interfaces through which users interact with computers and other technologies.

Techopedia Explains User Interface Design (UI Design)

In general, UI design principles revolve around a user-friendly result. Developers and engineers should look at what is most convenient for a user audience, as well as the requirements of the system and other aspects of research that feed into UI design.