WordNet (r) 3.0 (2006):

demo
    n 1: a visual presentation showing how something works; "the
         lecture was accompanied by dramatic demonstrations"; "the
         lecturer shot off a pistol as a demonstration of the
         startle response" [syn: demonstration, demo]
    v 1: give an exhibition of to an interested audience; "She shows
         her dogs frequently"; "We will demo the new software in
         Washington" [syn: show, demo, exhibit, present,
         demonstrate]

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

demo
 /de'moh/

    [short for ?demonstration?]

    1. v. To demonstrate a product or prototype. A far more effective way of
    inducing bugs to manifest than any number of test runs, especially when
    important people are watching.

    2. n. The act of demoing. ?I've gotta give a demo of the drool-proof
    interface; how does it work again??

    3. n. Esp. as demo version, can refer either to an early, barely-functional
    version of a program which can be used for demonstration purposes as long
    as the operator uses exactly the right commands and skirts its numerous
    bugs, deficiencies, and unimplemented portions, or to a special version of
    a program (frequently with some features crippled) which is distributed at
    little or no cost to the user for enticement purposes.

    4. [demoscene] A sequence of demoeffects (usually) combined with
    self-composed music and hand-drawn (?pixelated?) graphics. These days
    (1997) usually built to attend a compo. Often called eurodemos outside
    Europe, as most of the demoscene activity seems to have gathered in
    northern Europe and especially Scandinavia. See also intro, dentro.


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

demo

   /de'moh/ 1. A demonstration of a product, often of an early
   version or prototype.  A demo is a far more effective way of
   inducing bugs to manifest themselves than any number of test
   runs, especially when important people are watching.

   2. demo version.

   3. A program written to demonstrate the programmer's coding
   ability and/or the power of the computer it runs on.  Such
   demos are nearly always written in machine code and
   traditionally feature scrolling text about the author, his
   friends, his code and anything else he fancies and animated
   graphics.

   [Jargon File]

   (1994-11-04)