It's my pleasure to welcome you to the world of Linux. Linux is a family of open source Unix-like operating systems based on the Linux kernel, an operating systen kernel first release on September 17th, 1991 by Linus Torvalds. Linux is typically packaged in a Linux distribution.
Distributions include the Linux kernel and supporting system software and libraries, many of which are provided by the GNU Project. Many Linux distributions use the word "Linux" in their name, but the Free Software Foundation uses the name GNU/Linux to emphasize the importance of GNU software, causing some controversy.