What is GNU?
GNU is a Unix-like operating system that
is free software—it
respects your freedom. You can install
versions of GNU (more precisely, GNU/Linux systems) which are
entirely free software.
The GNU Project was launched in 1984 to
develop the GNU system. The name “GNU” is a recursive
acronym for “GNU's Not
Unix!”.

A Unix-like operating system is a software
collection of applications, libraries, and developer tools, plus a
program to allocate resources and talk to the hardware, known as a
kernel.
GNU is typically used with a kernel called Linux. This combination
is the GNU/Linux operating
system. GNU/Linux is used by millions, though
many call it “Linux” by
mistake.
GNU's own kernel, The Hurd
continues to be developed because it is an interesting technical
project.
What is Free Software?
“Free software”
is a matter of liberty, not price. To understand the concept, you
should think of “free” as in “free speech”,
not as in “free beer”.
Free software is a matter of the users' freedom to run,
copy, distribute, study, change and improve the software. More
precisely, it refers to four kinds of freedom, for the users of the
software:
- The freedom to run the program as you wish,
for any purpose (freedom 0).
- The freedom to study how the program works, and adapt it to your needs
(freedom 1). Access to the source code is a precondition for this.
- The freedom to redistribute copies so you can help your neighbor
(freedom 2).
- The freedom to improve the program, and release your improvements
to the public, so that the whole community benefits
(freedom 3). Access to the source code is a precondition for this.
How to pronounce GNU
“GNU” is
pronounced g'noo, as one syllable, like saying “grew” but
replacing the r with n.