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
Debian GNU/Linux provides more than a pure OS: it comes with over
25000 packages, precompiled software bundled
up in a nice format for easy installation on your machine.