WordNet (r) 3.0 (2006):

UNIX
    n 1: trademark for a powerful operating system [syn: UNIX,
         UNIX system, UNIX operating system]

The Jargon File (version 4.4.7, 29 Dec 2003):

Unix
 /yoo'niks/, n.

    [In the authors' words, ?A weak pun on Multics?; very early on it was ?
    UNICS?] (also ?UNIX?) An interactive timesharing system invented in 1969 by
    Ken Thompson after Bell Labs left the Multics project, originally so he
    could play games on his scavenged PDP-7. Dennis Ritchie, the inventor of C,
    is considered a co-author of the system. The turning point in Unix's
    history came when it was reimplemented almost entirely in C during
    1972?1974, making it the first source-portable OS. Unix subsequently
    underwent mutations and expansions at the hands of many different people,
    resulting in a uniquely flexible and developer-friendly environment. By
    1991, Unix had become the most widely used multiuser general-purpose
    operating system in the world ? and since 1996 the variant called Linux
    has been at the cutting edge of the open source movement. Many people
    consider the success of Unix the most important victory yet of hackerdom
    over industry opposition (but see Unix weenie and Unix conspiracy for
    an opposing point of view). See Version 7, BSD, Linux.

    [richiethom]

    Archetypal hackers ken (left) and dmr (right).

    Some people are confused over whether this word is appropriately ?UNIX? or
    ?Unix?; both forms are common, and used interchangeably. Dennis Ritchie
    says that the ?UNIX? spelling originally happened in CACM's 1974 paper The
    UNIX Time-Sharing System because ?we had a new typesetter and troff had
    just been invented and we were intoxicated by being able to produce small
    caps.? Later, dmr tried to get the spelling changed to ?Unix? in a couple
    of Bell Labs papers, on the grounds that the word is not acronymic. He
    failed, and eventually (his words) ?wimped out? on the issue. So, while the
    trademark today is ?UNIX?, both capitalizations are grounded in ancient
    usage; the Jargon File uses ?Unix? in deference to dmr's wishes.


The Free On-line Dictionary of Computing (30 December 2018):

Unix

    /yoo'niks/ (Or "UNIX", in the authors'
   words, "A weak pun on Multics") Plural "Unices".  An
   interactive time-sharing operating system invented in 1969
   by Ken Thompson after Bell Labs left the Multics
   project, originally so he could play games on his scavenged
   PDP-7.  Dennis Ritchie, the inventor of C, is considered
   a co-author of the system.

   The turning point in Unix's history came when it was
   reimplemented almost entirely in C during 1972 - 1974, making
   it the first source-portable OS.  Unix subsequently
   underwent mutations and expansions at the hands of many
   different people, resulting in a uniquely flexible and
   developer-friendly environment.

   By 1991, Unix had become the most widely used multi-user
   general-purpose operating system in the world.  Many people
   consider this the most important victory yet of hackerdom over
   industry opposition (but see Unix weenie and Unix
   conspiracy for an opposing point of view).

   Unix is now offered by many manufacturers and is the subject
   of an international standardisation effort [called?].
   Unix-like operating systems include AIX, A/UX, BSD,
   Debian, FreeBSD, GNU, HP-UX, Linux, NetBSD,
   NEXTSTEP, OpenBSD, OPENSTEP, OSF, POSIX, RISCiX,
   Solaris, SunOS, System V, Ultrix, USG Unix, Version
   7, Xenix.

   "Unix" or "UNIX"?  Both seem roughly equally popular, perhaps
   with a historical bias toward the latter.  "UNIX" is a
   registered trademark of The Open Group, however, since it is
   a name and not an acronym, "Unix" has been adopted in this
   dictionary except where a larger name includes it in upper
   case.  Since the OS is case-sensitive and exists in many
   different versions, it is fitting that its name should reflect
   this.

   The UNIX Reference Desk
   (http://geek-girl.com/unix.html).

   Spanish fire extinguisher

(ftp://linux.mathematik.tu-darmstadt.de/pub/linux/people/okir/unix_flame.gif).

   [Jargon File]

   (2001-05-14)