Object-oriented user interface
In computing, an object-oriented user interface (OOUI) is a type of user interface based on an object-oriented programming metaphor, and describes most modern operating systems ("object-oriented operating systems") such as MacOS and Unix. In an OOUI, the user interacts explicitly with objects that represent entities in the domain that the application is concerned with.
Source: Wikipedia — Object-oriented user interface (CC BY-SA 4.0)