Originally an adjective meaning an individual spoke many languages. More recent an adjective meaning that a file of SourceCode was valid in many ProgrammingLanguages
The 
original polyglot is valid code in 8 languages.
(*O/*_/
Cu #%* )pop mark/CuG 4 def/# 2 def%%%%@@P[TX---P\P_SXPY!Ex(mx2ex("SX!Ex4P)Ex=
CuG #%* *+Ex=
CuG #%*------------------------------------------------------------------*+Ex=
CuG #%* POLYGLOT - a program in eight languages 15 February 1991 *+Ex=
CuG #%* 10th Anniversary Edition 1 December 2001 *+Ex=
CuG #%* *+Ex=
CuG #%* Written by Kevin Bungard, Peter Lisle, and Chris Tham *+Ex=
CuG #%* *+Ex=
CuG #%* Polyglot suports the following languages: *+Ex=
CuG #%* 1. COBOL (ANSI) *+Ex=
CuG #%* 2. Pascal (ISO) *+Ex=
CuG #%* 3. Fortran (ANSI, f77) *+Ex=
CuG #%* 4. C (ANSI-ish) *+Ex=
CuG #%* 5. PostScript *+Ex=
CuG #%* 6. Linux/Unix shell script (bash, sh, csh) *+Ex=
CuG #%* 7. x86 machine language (MS-DOS, Win32, Linux) *+Ex=
CuG #%* 8. Perl (version 5) *+Ex=
CuG #%* *+Ex=
CuG #%* Usage: *+Ex=
CuG #%* 1. Rename this file to polyglot.[cob|pas|f77|c|ps|sh|com|pl] *+Ex=
CuG #%* *+Ex=
CuG #%* 2. Compile and run with your favorite compiler and operating *+Ex=
CuG #%* system. *+Ex=
CuG #%* *+Ex=
CuG #%* Notes: *+Ex=
CuG #%* 1. We have attempted to use only standard language features. *+Ex=
CuG #%* *+Ex=
CuG #%* 2. Without the -traditional flag gcc will issue a warning. *+Ex=
CuG #%* *+Ex=
CuG #%* 3. When transferring from Unix to DOS make sure that a LF *+Ex=
CuG #%* is correctly translated into a CR/LF. *+Ex=
CuG #%* *+Ex=
CuG #%* 4. Keep the black lines at the start of the program. They *+Ex=
CuG #%* are important. *+Ex=
CuG #%* *+Ex=
CuG #%* 5. This text is a comment block in all eight languages. *+Ex=
CuG #%* *+Ex=
CuG #%* Please mail any comments, corrections or additions to *+Ex=
CuG #%* polyglot@ideology.com.au *+Ex=
CuG #%* *+Ex=
CuG #%*------------------------------------------------------------------*QuZ=
CuG #%* *+Ex=
CuG #%*!Mx)ExQX5ZZ5SSP5n*5X!)Ex+ExPQXH,B+ExP[-9A-9B(g?(gA'UTTER_XYZZXX!X *+
CuG #(* *(
C # */); /*(
C # *) program polyglot (output); (*+
C # identification division.
C # program-id. polyglot.
C #
C # data division.
C # procedure division.
C #
C # * ))cleartomark /Bookman-Demi findfont 36 scalefont setfont (
C # * (
C #
C # * hello polyglots$
C # main.
C # perform
C /# * ) 2>_$$; echo "hello polyglots"; rm _$$; exit;
C # * (
C #
C *0 ) unless print "hello polyglots\n"; __END__
print
C stop run.
-*, 'hello polyglots'
C
C print.
C display "hello polyglots". (
C */ int i; /*
C */ main () { /*
C */ i=printf ("hello polyglots\n"); O= &i; return *O; /*
C *) (*
C *) begin (*
C *) writeln ('hello polyglots'); (*
C *) (* )
C * ) pop 60 360 (
C * ) pop moveto (hello polyglots) show (
C * ) pop showpage ((
C *)
end .(* )
C)pop% program polyglot. *){*/}
gcc -xc polyglot.src -o polyglot && ./polyglot
The -xc switch forces the language to be C.
gv polyglot.src
sh polyglot.src # or chmod +x polyglot.src && ./polyglot.src
Etc...
The following is a polyglotic quine. (A quine is a program that prints its own source code out when run, without cheating by using open(2) on itself.)
#include <stdio.h>
#define q(a,...) a
#define substr q
#define eval(a) main(){char c[]=a,n=10;c[419]=0;printf(c+4,n,n,n,n,34,34,n,34,39,c+4,39,34,n);}/* Copyright (C) Thomas Schumm <phong@phong.org>
exec("from sys import*;substr=q=lambda y:exit(stdout.write(y[4:-46]%((10,)*4+(34,34,10,34,39,y[4:-46],39,34,10))))",None);#*/
eval(substr(q("$p='#include <stdio.h>%c#define q(a,...) a%c#define substr q%c#define eval(a) main(){char c[]=a,n=10;c[419]=0;printf(c+4,n,n,n,n,34,34,n,34,39,c+4,39,34,n);}/* Copyright (C) Thomas Schumm <phong@phong.org>%cexec(%cfrom sys import*;substr=q=lambda y:exit(stdout.write(y[4:-46]%%((10,)*4+(34,34,10,34,39,y[4:-46],39,34,10))))%c,None);#*/%ceval(substr(q(%c$p=%c%s%c;printf($p,(10)x4,34,34,10,34,39,$p,39,34,10)%c),1,-1))%c';printf($p,(10)x4,34,34,10,34,39,$p,39,34,10)"),1,-1))
2 pages link to PolyGlot:
