the penny drops

the penny drops

1. (UK, informal) Understanding is reached; one comprehends.

   The penny dropped as Fred realised he had been conned.

   • 1979, Dervla Murphy, Wheels Within Wheels, page 56:

     Suddenly various pennies began to drop; now I understood obscure remarks that had been made in my presence by the Ryans, or by the nuns at school, or by Old Brigid or Tommy's foster-mother.

   • 2011 August 27 (broadcast date), Doctor Who, series 6, episode 8, Let's Kill Hitler:

     AMY: In the time I've known you, when have you shown the slightest interest in a girl?

     MELS: Penny in the air!

     AMY: I've known you for, what, 10 years? I've seen you practically every day. Name one girl you've paid the slightest bit of attention to? (RORY is flustered, runs from the room.)

     AMY: Oh my God! Rory! (AMY runs after RORY.)

     MELS: And the penny drops!

• May be used with variable tense and aspect: "the penny dropped", "the penny has dropped", "the penny would have dropped", etc.

• “the penny drops”, in Cambridge English Dictionary, Cambridge, Cambridgeshire: Cambridge University Press, 1999–present.
• “the penny drops”, in Merriam-Webster Online Dictionary, Springfield, Mass.: Merriam-Webster, 1996–present.
• “the penny has dropped” in Longman Dictionary of Contemporary English, Longman.