The word geek is a slang term, noting individuals as "One who is perceived to be overly obsessed with one or more things including those of intellectuality, electronics, etc." Formerly, the term referred to a carnival performer often billed as a wild man whose act usually includes biting the head off a live chicken, bat, snake or bugs. The 1976 edition of the American Heritage Dictionary included only the definition regarding geek shows.

This word comes from English dialect geek, geck: fool, freak; from Low German geck, from Middle Low German. The root geck still survives in Dutch and Afrikaans gek: crazy, as well as some German dialects, and in the Alsatian word Gickeleshut: geek's hat, used in carnivals.

Although often considered as a pejorative, the term is also often used self-referentially without malice- an example is the 'Geek Squad' of the Best Buy company.