Easter Egg Definition

A virtual Easter egg is an intentional hidden message, in-joke, or feature in a work such as a computer program, web page, video game, movie, book, or crossword. The term was coined—according to Warren Robinett—by Atari after they were pointed to the secret message left by Robinett in the game Adventure. It draws a parallel with the custom of the Easter egg hunt observed in many Western nations as well as the last Russian imperial family's tradition of giving elaborately jeweled egg-shaped creations by Carl Fabergé which contained hidden surprises.

This practice is similar in some respects to hidden signature motifs such as Diego Rivera including himself in his murals, Alfred Hitchcock's legendary cameo appearances, the appearances of Fritz in the works of Chris van Allsburg, and various "Hidden Mickeys" that can be found throughout the various Disney Parks. An early example of this kind of "Easter egg" is Al Hirschfeld's "Nina".

Atari's Adventure, released in 1979, contained what was thought to be the first video game "Easter egg", the name of the programmer (Warren Robinett). However, evidence of earlier Easter eggs has since surfaced. Several cartridges for the Fairchild Channel Finclude previously unknown Easter eggs, programmed by Michael Glass and Brad Reid-Selth, that are believed to predate Robinett's work.