Do not take our word on Linux here is a list of definitions on what Linux is with associated links.

A version of UNIX that has gained popularity because of its stability as an operating system for hosting web servers. Linux is open source software and is freely available over the Internet.
www.oit.ohio-state.edu/glossary/gloss2.html

Linux is an open-source operating system derived from the Unix operating system. It is used most commonly to run servers.
iet.ucdavis.edu/glossary/

A UNIX-like operating system. Very efficient and fast-performing system.
www.cctvconsult.com/glossary.htm

A freeware clone of UNIX for 386-based PC computers. Linux consists of the linux kernel (core operating system), originally written by Linus Torvalds, along with utility programs developed by the Free Software Foundation and by others. Since PC hardware is inexpensive and linux is essentially free the combination of the two is a practical way of developing inexpensive and reliable HTTP service.
www.utoronto.ca/ian/books/xhtml1/gloss/gloss.html

Linux is an open source operating system within the Unix family. Because of its robustness and availability, Linux has won popularity in the open source community and among commercial application developers.
www.axis.com/corporate/corp/glossary_general.htm

A free Unix- type operating system originally created by Linus Torvalds with the assistance of developers around the world. Developed under the GNU General Public License , the source code for Linux is freely available to everyone. [Linux Home Page] http://www.linux.org/
www.genomicglossaries.com/content/computers.asp

An Open Source implementation of UNIX initiated by Linus Torvalds, which runs on many different hardware platforms including Intel, Sparc®, PowerPC, and Alpha Processors. Hundreds of application programs have been written for Linux, some of these by the GNU project. Linux's architecture like LNA creates a more reliable system. Systems using protected memory and pre-emptive multitasking are inherently more stable. Because the source to Linux is open source, it is easy to customize and to update rapidly (total cost of ownership is also low). This flexibility has enabled Linux to run on everything from handheld and embedded systems to clusters of hundreds of servers. LNA uses on the server side (Linbox NetServer) an industry- standard platforms running the Linux operating system.
www.linbox.com/en/about/glossary.html

Linux is a new operating system developed by a Norwegian programmer named Linus Torvald. Linux is free and the source code is all 'open'. That is, any one can work on the Linux operating system and then post new code to improve it. This concept is known as 'Open Source'. IBM has adopted Linux as a standard. It is a new system and there are tradeoffs to using it. It is hard to install and it is still being tested. But it very useful, and it is free.
www.rustybrick.com/definitions.php

A free version of the Unix operating system, primarily composed of tools developed over a 15-year period by Richard Stallman and Project GNU. However, the final spectacular push was provided by Linus Torvalds who wrote a kernel (completed in 1994), organized a bunch of programmers Internet-wide, and managed releases.
philip.greenspun.com/internet-application-workbook/glossary

A version of UNIX that runs on a variety of hardware platforms including x86 PCs, Alpha, PowerPC and IBM's product line. Linux is open source software, which is freely available; however, the full distribution of Linux along with technical support and training are available for a fee from vendors such as Red Hat Software and Caldera. Due to its stability, Linux has gained popularity with ISPs as the OS for hosting Web servers.
www.course.com/careers/glossary/operating.cfm

A UNIX-like operating system that was designed by Linus Torvalds at the University of Helsinki to provide PC users with a free or very low-cost operating system comparable to UNIX systems. Unlike Microsoft Windows LINUX is extendible by contributors. LINUX is sometimes suggested as a possible publicly-developed alternative to the desktop predominance of Microsoft Windows.
www.pads.ahds.ac.uk:81/glossary2.html

A free UNIX operating system.
tao.atmos.washington.edu/computer_helps/glossary.html

– An open source UNIX-like kernel, originally begun by Linus Torvalds. Often used to mean the whole operating system, GNU/Linux. Thousands of people have contributed to the development of the Linux kernel, and new versions are released every few weeks.
www.newtolinux.org.uk/glossary.shtml

A freely available Unix-like operating system based on a kernel originally written for the Intel 386 architecture by (then) student Linus Torvalds. Once his 32-bit kernel was available, the GNU utilities made it a usable system and contributions from many others led to explosive growth. Today Linux is a complete Unix replacement available for several CPU architectures -- Intel, DEC/Compaq Alpha, Power PC, both 32-bit SPARC and the 64-bit UltraSPARC, SrongARM, . . . -- with support for multiple CPUs on some architectures. Linux FreeS/WAN is intended to run on all CPUs supported by Linux and is currently (February 1999) known to work on Intel, Alpha and StrongARM. See our compatibility document for details.
www.freeswan.org/freeswan_trees/freeswan-1.5/doc/glossary.html

A popular operating system based on the UNIX operating system. It, like Windows, supports a GUI (Graphic User Interface). Linux has the advantage of being Open Source, which means the source code is available for download.
www.ravensearch.net/metaglossary.html

Linux Is Not UniX? A Unix-like operating system first developed, still maintained by, and named after Linus Torvalds. It is freely available under the General Public License. But if you didn't know all that already, what are you doing here?
www.piensa.com/lpi/p-glossary.html

A Unix-like operating system whose source code is freely available, used for networking, software development, and as an end-user platform. Popular for its low cost, functionality and reliability, it is also being considered for some real-time applications.Compared to a dedicated real-time operating system like QNX, Linux has a larger memory footprint, is more difficult to boot from ROM, and services like semaphores are not currently allocated by priority (though this is being discussed). Priorities of all drivers (I/O devices, and filesystems) as well of networking cannot be controlled.Cogent software running on Linux uses the S/R/R Module to emulate QNX send/receive/reply real-time message passing.
developers.cogentrts.com/cogent/cogentdocs/gl-defs.html

An open source spin-off of the UNIX operating system that runs on a number of hardware platforms and is made available for free over the Internet.
247.aw.com/html/glossary/l_gloss.html

A version of the Unix operating system designed to run on PCs. Controversial because it has been developed as part of the Open Sources movement and given away free of charge. Very popular for Web servers and appliances.
www.mantex.co.uk/samples/glo-3.htm

A free operating system where improvement is freely accepted, yet credited. Originally developed by Linus Torvalds.
www.webhosting.net/25.html

A freeware version of Unix, Linux is becoming popular as a powerful, low-cost operating system for running servers.
www.ntius.com/support/glossary/internet_glossary.htm

A full-featured, robust, freely-available operating system originally developed by Linus Torvalds.
www.linux.cu/documentos/RedHat/gsg/ch-glossary.htm

– A computer operating system distinguished from other operating systems (such as Windows or Unix) by the fact that its source code is available to anyone, and anyone can contribute improvements to the system.
www.consumergoods.com/2003_CG_SB/CG2003glossary.html

is a UNIX-like operating system that was designed to provide personal computer users a free or very low-cost operating system comparable to traditional and usually more expensive UNIX systems.
www.cybermall.co.nz/hosting/glossary.html

A UNIX based Operating system designed and built in co-operative open-source style. Touted to become as big as Windows and it's not doing a bad job. It's used as a server and odd-job man at bownie.com but there's lots of software available for it too. The music software is getting there.. See www.linux.org for more details on this fine operating system. Back
www.bownie.com/guide/glossary/bdc-RG-glossary-L.shtml

an open-source version of the UNIX operating system
www.cogsci.princeton.edu/cgi-bin/webwn