Glossary

FSF - Free Software Foundation.  The non-profit organization behind GNU and the GPL.

GNU - GNU's Not Unix.  A free clone of Unix, licensed under the GPL.  GNU has its own kernel, which was only recently finished (as far as I know), called HURD.

GNU/Linux - A term sometimes used to refer to the combination of the Linux kernel and various software components from GNU.  This term was suggested by the Free Software Foundation to emphasize that Linux is only one part of a much larger system.

GPL - GNU General Public License.  A particular open-source software license that requires that if altered software covered by the license is distributed to the public, the altered source code for the software must be made publicly available.  The license was made in response to the commercial forking of Unix into a number of separate, somewhat incompatible versions.  The license prevents software from becoming controlled by any one company or entity.

Kernel - The basic core of an operating system.  An operating system generally consists of a kernel and numerous additional software components.

Linus Torvalds - The creator of the original Linux kernel, which he made in 1991 while a graduate student in Finland.  Linus owns the copyright to the name "Linux".  The name, which was suggested by early Linux developers, is a light-hearted play on the names "Linus" and "Unix".  Linus has the final say on what modifications get added to the official Linux kernel.

Linux - A free clone of the Unix kernel, licensed under the GPL.  Linux was originally written specifically for 386 PCs, but was later ported to a wide variety of hardware platforms.  Generally, the term "Linux" is used to refer to both the kernel and the surrounding components of the operating system, although technically Linux is just the kernel itself.  Linux is pronounced "LINN-ucks".

OSS - Open-Source Software.  Software in which the users have unrestricted and unconditional freedom to view the source code.  Usually the user can also modify the software and sell it.

Richard Stallman - The originator of the Free Software Foundation.  Also responsible for much of the work to develop GNU and the GPL.

Tux - "Tux" is the name of the penguin that's the official Linux mascot.  Tux is a harmless, good-natured penguin that usually looks pleasantly stuffed from a good meal of fish.  The mascot was chosen by Linus to portray a very unthreatening, unhostile image.