Debian is a free operating system (OS) for your computer. An operating system is the set of basic programs and utilities that make your computer run. Debian uses the Linux kernel (the core of an operating system), but most of the basic OS tools come from the GNU project; hence the name GNU/Linux.
Linux (commonly pronounced /ˈlɪnəks/ LIN-əks in American English,[4][5] also pronounced /ˈlɪnʊks/ LIN-ooks[6] in Europe and Canada) is a generic term referring to the family of Unix-like computer operating systems based on the Linux kernel.
What does GNU/Linux refer to?
GNU/Linux is the name Richard Stallman, founder of the Free Software Foundation and the GNU project, and its supporters prefer over just Linux. They cite the fact that Linux could not have come into being without tools from the GNU project. Though this is true, use and custom has favored just Linux over GNU/Linux in the public consciousness. This website's use of the term Linux in no way tries to minimize the contributions of the Free Software Foundation. We feel that it's easier for people to identify the operating system by that simpler name and in the end, that helps in its adoption.