Linux is OS (operating system), that is free and respects your privacy. It has one of the most powerful communities. It's stable, safer, respects privacy and can offer more than other operating systems. Linux have a lot of diffrent kinds, because it's maintaned by community. Name for all of those kinds is distributions (distros for short). Because of that you can choos one that will fit your needs perfectly. You can customize it in every way you like too.