GNU (pronounced g'nu ) is a free operating system consisting of a kernel, libraries, system utilities, compilers, and end-user applications. Its name is a recursive acronym for "GNU's Not Unix",

It was chosen because its design is Unix-like, but differs from Unix by being free software and by not containing any UNIX code. The plan for the GNU operating system was announced in September 1983 by Richard Stallman and software development work began in January 1984. As of 2006, GNU is being actively developed. The project to develop GNU is known as the GNU Project, and programs released under the auspices of the GNU Project are called GNU packages or GNU programs.

For more, go to Wikipedia's entry on this term.

We all love Richard Stallman as he is a paragon of ethical computing. Promoting freedom and sharing via means of intellectual property law Stallman has shown us that software can be free and so can we!