WordNet (r) 3.0 (2006):

Quine
    n 1: United States philosopher and logician who championed an
         empirical view of knowledge that depended on language
         (1908-2001) [syn: Quine, W. V. Quine, Willard Van
         Orman Quine]

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

quine
 /kwi:n/, n.

    [from the name of the logician Willard van Orman Quine, via Douglas
    Hofstadter] A program that generates a copy of its own source text as its
    complete output. Devising the shortest possible quine in some given
    programming language is a common hackish amusement. (We ignore some
    variants of BASIC in which a program consisting of a single empty string
    literal reproduces itself trivially.) Here is one classic quine:

    ((lambda (x)
      (list x (list (quote quote) x)))
     (quote
        (lambda (x)
          (list x (list (quote quote) x)))))

    This one works in LISP or Scheme. It's relatively easy to write quines in
    other languages such as Postscript which readily handle programs as data;
    much harder (and thus more challenging!) in languages like C which do not.
    Here is a classic C quine for ASCII machines:

    char*f="char*f=%c%s%c;main()
    printf(f,34,f,34,10);%c";
    main()printf(f,34,f,34,10);

    For excruciatingly exact quinishness, remove the interior line breaks. Here
    is another elegant quine in ANSI C:

    #define q(k)main()return!puts(#k"\nq("#k")");
    q(#define q(k)main()return!puts(#k"\nq("#k")");)

    Some infamous Obfuscated C Contest entries have been quines that
    reproduced in exotic ways. There is an amusing Quine Home Page.


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

quine

    /kwi:n/ (After the logician Willard V. Quine,
   via Douglas Hofstadter) A program that generates a copy of its
   own source text as its complete output.  Devising the shortest
   possible quine in some given programming language is a common
   hackish amusement.

   In most interpreted languages, any constant, e.g. 42, is a
   quine because it "evaluates to itself".  In certain Lisp
   dialects (e.g. Emacs Lisp), the symbols "nil" and "t" are
   "self-quoting", i.e. they are both a symbol and also the value
   of that symbol.  In some dialects, the function-forming
   function symbol, "lambda" is self-quoting so that, when
   applied to some arguments, it returns itself applied to those
   arguments.  Here is a quine in Lisp using this idea:

    ((lambda (x) (list x x)) (lambda (x) (list x x)))

   Compare this to the lambda expression:

   	(\ x . x x) (\ x . x x)

   which reproduces itself after one step of beta reduction.
   This is simply the result of applying the combinator fix
   to the identity function.  In fact any quine can be
   considered as a fixed point of the language's evaluation
   mechanism.

   We can write this in Lisp:

    ((lambda (x) (funcall x x)) (lambda (x) (funcall x x)))

   where "funcall" applies its first argument to the rest of its
   arguments, but evaluation of this expression will never
   terminate so it cannot be called a quine.

   Here is a more complex version of the above Lisp quine, which
   will work in Scheme and other Lisps where "lambda" is not
   self-quoting:

    ((lambda (x)
      (list x (list (quote quote) x)))
     (quote
        (lambda (x)
          (list x (list (quote quote) x)))))

   It's relatively easy to write quines in other languages such
   as PostScript which readily handle programs as data; much
   harder (and thus more challenging!) in languages like C
   which do not.  Here is a classic C quine for ASCII
   machines:

    char*f="char*f=%c%s%c;main() printf(f,34,f,34,10);%c";
    main()printf(f,34,f,34,10);

   For excruciatingly exact quinishness, remove the interior line
   break.  Some infamous Obfuscated C Contest entries have been
   quines that reproduced in exotic ways.

   Ken Thompson's back door involved an interesting variant
   of a quine - a compiler which reproduced part of itself when
   compiling (a version of) itself.

   [Jargon File]

   (1995-04-25)