What in the heck is “GNU”?
“GNU” stands for “GNU’s Not Unix”, a geeky play on words. GNU defines a set of programs which do many of the tasks that Unix (an old commercially available computer operating system) programs do. Linux is a “Unix-like” operating system. Some people like to insist that everyone refer to Linux as GNU/Linux, although we think that’s a bit too anal-retentive for our tastes.