Mac OS X
Mac OS X is an operating system developed by Apple Inc. It is based on FreeBSD, an Unix-like operating system with a hybrid-kernel based on technologies NeXT Software, Inc. developed for its NEXTSTEP operating system, and code from the FreeBSD project. It currently ships with all new Macintosh computers. The current major version is 10.15 "Catalina". 
The graphical user interface in Mac OS X is called Aqua, which includes a Dashboard that allows for mini programs called Widgets to be placed on the desktop. All applications included in OS X follow a well defined set of Human Interface Guidelines giving them an intuitive, consistent user interface. Aqua also comes with a dock that allows users to quickly launch applications, and displays an icon or thumbnail for running software applications.