Where stable actually means stable! – Debian (by Software in the Public Interest).
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 provides more than a pure OS: it comes with over 51000 packages, precompiled software bundled up in a nice format for easy installation on your machine.
Between major releases your Debian stable system can be brought up to date via Debian Backports.