Basically, 'Linux' is the name given to any operating system which uses the 'Linux Kernel'. (A Kernel is the central part of a computer operating system, and makes everything else work). There are many Linux operating systems, most of them specifically aimed at a particular market or user, for example:

* Ubuntu Linux
Arguably the most popular and widely used Linux. Ideal for all uses, including in the home, the office, and as a server. Ubuntu is based upon another popular Linux distribution, Debian.

* Edubuntu Linux
Edubuntu is an official subproject of Ubuntu, aimed at the education market. This version features more educational and learning related applications which are installed by default, as compared to Ubuntu. This version is popular in schools, and for under 13's.

* SUSE Enterprise Desktop Linux
This distribution of Linux brings powerful enterprise/large business solutions to your desktop computer. Ideal for use in government offices, and other places with a high workload. Can also be used as a server.

The foundation beliefs with Linux is that operating systems and software should be free, and open source. Most, if not all, free and open source software - not just the Linux operating systems - is better than any commercial paid-for software. Developers innovate and enhance this technology, not for personal wealth and greed - but instead, for the benefit of humanity, and for their passion for advancing technology and making it the best it can be.

Open Source means the source code of the application / operating system is freely available to modify and redistribute, and is not plagued by patents, copyrights, and the terms and conditions of greedy corporations.

Read more about Linux on Wikipedia, here.