Bazinga is Sheldon Cooper's signature catchphrase from The Big Bang Theory, the long-running American sitcom centred on a group of scientifically minded friends. Sheldon uses the word to signal that a joke or prank was intentional, often after deliberately misleading another character. The catchphrase caught on with viewers and became one of the show's most quoted lines, later spreading through clips, memes, reaction videos and soundboards. It remains popular because it instantly frames a moment as a playful trick, even for people who have never watched the full series.