The point of interaction between a user and a computer system, typically consisting of graphical elements such as windows, menus, buttons, and controls, designed to facilitate user input and feedback.

"The UI of the application was intuitive and user-friendly, allowing users to easily navigate and perform tasks."

The means by which the user and a computer system interact, in particular the use of input devices and software.

"A well-designed UI can make software easy and intuitive to use, enhancing the user experience."