macguffin

/məˈɡʌfɪn/
noun
  1. An object, event, or character in a story that serves as the trigger for the plot, even though it may not be important in itself.
    • Writers often use a MacGuffin to give characters a reason to chase after something.
    • The briefcase in the film was a classic MacGuffin—everyone wanted it, but its contents were never revealed.
    • In many spy movies, the secret formula is just a MacGuffin that drives the action.
Synonyms
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