Linux (IPA pronunciation: /ˈlɪnʌks/) refers to any Unix-like computer operating system that uses the Linux kernel.

Initially developed and used primarily by individual enthusiasts on personal computers, Linux has since gained the support of corporations such as IBM, Sun Microsystems, Hewlett-Packard, and Novell, Inc., and has risen to prominence as an operating system for servers; Netcraft reported in September 2006 that eight of the ten most reliable internet hosting companies run Linux on their web servers.

Linux has been more widely ported to different computing platforms than any other operating system. It is used in devices ranging from supercomputers to mobile phones, and has a foothold in the personal computer and business desktop markets.

The Linux kernel is one of the most prominent examples of free software and of open source development; its underlying source code is available for anyone to use, modify, and redistribute freely.

Linux 7.0 reffers of the 7th version of an Linux operating system.

Check this sites for learning Linux:

http://www.linux.org/lessons/
http://www.learninglinux.com/

You can read here how to install openSUSE.