Which term refers to what the user sees and interacts with on a software application?

The term that refers to what the user sees and interacts with on a software application is the User Interface. This encompasses all the visual elements of a software application, including menus, buttons, icons, and the overall layout. The design of the user interface is crucial because it directly affects how users engage with the software. A well-designed user interface makes the application more intuitive and easier to navigate, allowing users to accomplish their tasks efficiently.

User Experience, while related, refers to the overall experience a user has with the application, including their feelings and perceptions when using it. System Interface is typically a term used to describe the interface between the software and the system it operates on, rather than the part that the end-user interacts with. Interaction Layer, though it might suggest user interaction, is not a standard term to describe the visible part of a software application and is less commonly used.

Therefore, the definitive term for the aspect of an application that users see and engage with is the User Interface.