What Does Debian GNU/Linux Mean?

Built on the Linux kernel, Debian GNU/Linux is an open-source and free operating system (OS) that is based on a graphical user interface (GUI). It incorporates GNU project tools and capabilities and is packaged with thousands of software applications for easy installation and execution.

Techopedia Explains Debian GNU/Linux

Released in 1993 by the Debian Project, Debian is a Linux distribution that evolved from the Unix OS. It may be used as a desktop, server or embedded OS and supports a number of processor frameworks, including Intel, AMD and ARM.