n. 1. A message hidden in the object code of a program
as a joke, intended to be found by persons disassembling or
browsing the code
.
2. A message, graphic, or sound effect emitted
by a program (or, on a PC, the BIOS ROM) in response to some
undocumented set of commands or keystrokes, intended as a joke or
to display program credits. One well-known early Easter egg found
in a couple of OSes caused them to respond to the command
'make love' with 'not war?'. Many personal computers
have much more elaborate eggs hidden in ROM, including lists of the
developers' names, political exhortations, snatches of music, and
(in one case) graphics images of the entire development team.