A MacGuffin is a plot device used to motivate action and move a story along.

It might be secret documents stolen by enemy agents. It could be hidden treasure. It can be a character’s mistaken belief that another person is out to get them.

Whatever it is, it’s exact nature is often almost irrelevant in terms of the story’s outcome. Sometimes it’s never even revealed what it is. For instance, the viewer never finds out what’s actually in the briefcase pursued by characters in the movie Pulp Fiction.

So where does the word MacGuffin come from?

The word guff means nonsense, something made up. A MacGuffin was first described in 1939 by film director Alfred Hitchcock (The Birds, North By Northwest, Psycho), and the invention of the word (though not the method of such a plot device) is generally ascribed to him.

There is some dispute over this, however. Wikipedia credits British screenwriter Angus MacPhail with coining the term, based on a 1990 interview with MacPhail’s associate Ivor Montagu about working with Hitchcock.

In the 1920s and ‘30s, the trio met regularly for script and story development conferences. Montagu, who defined a MacGuffin as ‘an unknown plot objective which you did not need to choose until the story planning was complete’, asserted MacPhail made up the word, after which it was gleefully adopted by the director.