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

TeX
 /tekh/, n.

    An extremely powerful macro-based text formatter written by Donald E. 
    Knuth, very popular in the computer-science community (it is good enough
    to have displaced Unix troff, the other favored formatter, even at many
    Unix installations). TeX fans insist on the correct (guttural)
    pronunciation, and the correct spelling (all caps, squished together, with
    the E depressed below the baseline; the mixed-case ?TeX? is considered an
    acceptable kluge on ASCII-only devices). Fans like to proliferate names
    from the word ?TeX? ? such as TeXnician (TeX user), TeXhacker (TeX
    programmer), TeXmaster (competent TeX programmer), TeXhax, and TeXnique.
    See also CrApTeX.

    Knuth began TeX because he had become annoyed at the declining quality of
    the typesetting in volumes I--III of his monumental Art of Computer
    Programming (see Knuth, also bible). In a manifestation of the typical
    hackish urge to solve the problem at hand once and for all, he began to
    design his own typesetting language. He thought he would finish it on his
    sabbatical in 1978; he was wrong by only about 8 years. The language was
    finally frozen around 1985, but volume IV of The Art of Computer
    Programming is not expected to appear until 2007. The impact and influence
    of TeX's design has been such that nobody minds this very much. Many grand
    hackish projects have started as a bit of toolsmithing on the way to
    something else; Knuth's diversion was simply on a grander scale than most.

    TeX has also been a noteworthy example of free, shared, but high-quality
    software. Knuth offers a monetary award to anyone who found and reported
    bugs dating from before the 1989 code freeze; as the years wore on and the
    few remaining bugs were fixed (and new ones even harder to find), the bribe
    went up. Though well-written, TeX is so large (and so full of cutting edge
    technique) that it is said to have unearthed at least one bug in every
    Pascal system it has been compiled with.


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

TeX

    /tekh/ An extremely powerful macro-based text
   formatter written by Donald Knuth, very popular in academia,
   especially in the computer-science community (it is good
   enough to have displaced Unix troff, the other favoured
   formatter, even at many Unix installations).

   The first version of TeX was written in the programming
   language SAIL, to run on a PDP-10 under Stanford's WAITS
   operating system.

   Knuth began TeX because he had become annoyed at the declining
   quality of the typesetting in volumes I-III of his monumental
   "Art of Computer Programming" (see Knuth, also bible).  In
   a manifestation of the typical hackish urge to solve the
   problem at hand once and for all, he began to design his own
   typesetting language.  He thought he would finish it on his
   sabbatical in 1978; he was wrong by only about 8 years.  The
   language was finally frozen around 1985, but volume IV of "The
   Art of Computer Programming" has yet to appear as of mid-1997.
   (However, the third edition of volumes I and II have come
   out).  The impact and influence of TeX's design has been such
   that nobody minds this very much.  Many grand hackish projects
   have started as a bit of toolsmithing on the way to
   something else; Knuth's diversion was simply on a grander
   scale than most.

   Guy Steele happened to be at Stanford during the summer of
   1978, when Knuth was developing his first version of TeX.
   When he returned to MIT that fall, he rewrote TeX's I/O to
   run under ITS.

   TeX has also been a noteworthy example of free, shared, but
   high-quality software.  Knuth offers monetary awards to people
   who find and report a bug in it: for each bug the award is
   doubled.  (This has not made Knuth poor, however, as there
   have been very few bugs and in any case a cheque proving that
   the owner found a bug in TeX is rarely cashed).  Though
   well-written, TeX is so large (and so full of cutting edge
   technique) that it is said to have unearthed at least one bug
   in every Pascal system it has been compiled with.

   TeX fans insist on the correct (guttural) pronunciation, and
   the correct spelling (all caps, squished together, with the E
   depressed below the baseline; the mixed-case "TeX" is
   considered an acceptable kluge on ASCII-only devices).
   Fans like to proliferate names from the word "TeX" - such as
   TeXnician (TeX user), TeXhacker (TeX programmer), TeXmaster
   (competent TeX programmer), TeXhax, and TeXnique.

   Several document processing systems are based on TeX, notably
   LaTeX Lamport TeX - incorporates document styles for books,
   letters, slides, etc., jadeTeX uses TeX as a backend for
   printing from James' DSSSL Engine, and Texinfo, the GNU
   document processing system.  Numerous extensions to TeX exist,
   among them BibTeX for bibliographies (distributed with
   LaTeX), PDFTeX modifies TeX to produce PDF and Omega
   extends TeX to use the Unicode character set.

   For some reason, TeX uses its own variant of the point, the
   TeX point.

   See also Comprehensive TeX Archive Network.

   (ftp://labrea.stanford.edu/tex/).

   E-mail:  (TeX User's group, Oregon, USA).

   (2002-03-11)