the penny drops

the penny drops

One finally understands, realizes, or recognizes something. Typically used in the past tense. When Liam drew the diagram, the penny dropped, and everything became clear to me.
See also: drop, penny
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.

the penny drops

mainly BRITISH
COMMON If the penny drops, someone finally understands or realizes something. In the end the penny dropped. That was why she sent us back. It's only recently the penny's begun to drop that, actually, the new job is probably better than the other one. Note: This expression probably refers to slot machines (= machines for playing games), which only operate when you put in a coin.
See also: drop, penny
Collins COBUILD Idioms Dictionary, 3rd ed. © HarperCollins Publishers 2012

the penny drops

someone finally realizes or understands something. informal, chiefly British
The image here is of the operation of a coin-operated slot machine.
See also: drop, penny
Farlex Partner Idioms Dictionary © Farlex 2017

the ˌpenny ˈdrops

(informal, especially British English) suddenly understand the meaning or significance of something: She never understands jokes. It usually takes about half an hour for the penny to drop.There was a long silence on the stage, and then the penny finally dropped — it was my turn to speak.
This is a comparison with the way a machine starts after a coin is inserted.
See also: drop, penny
Farlex Partner Idioms Dictionary © Farlex 2017

penny dropped, the

One finally catches on to something. The term alludes to old-time machines in which one deposited a penny to obtain a piece of candy, which one received after the penny dropped all the way down. Dating from the 1950s, it is used more in Britain than in the United States but is still current. Alexander McCall Smith used it in The Right Attitude to Rain (2006): “I think he realises now that she’s never going to come back to him. It’s taken a long time, but the penny has finally dropped.”
See also: penny
The Dictionary of Clichés by Christine Ammer Copyright © 2013 by Christine Ammer
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References in periodicals archive ?
The penny drops: he used her to get information on Jack.
Elsewhere, the penny drops for Chrissie and Rebecca that Robert, pictured, has seduced their father.
He may continue to burn a few fingers before the penny drops in terms of trapping.
Emmerdale Andy sees Aaron's mobile number in Robert's phone and the penny drops about his involvement in Katie's murder.
Before long, the penny drops and Mick and Tina go in search of Aunt Babe, but it turns out she's moved to Ramsgate.
As the penny drops that she could be pregnant she braces herself to do not one but three tests just to be sure.
SHOCK: Vanessa's As the penny drops that she could be pregnant she braces herself to do not one but three tests just to be sure, and her heart starts racing when her fears are confirmed.
This refers to 'Dance until the penny drops...' (Viewpoint, GDN February 10).
Finally the penny drops and this minister agrees with us.
At the hospital, Huw hears the nurse utter the word 'baby' as she sees to Lois and the penny drops.
The penny drops during Gennie and Jamie's leaving party, after she hugs Bob for a little too long.
As a Liverpool fan who made the effort to go to the game I saw the game against Leeds as just prolonging the agony before the penny drops and Gerard Houllier is shown the door.
EMMERDALE (ITV, 7pm and 8pm) THE gig is finally up for Paddy after the penny drops for Rhona.
At first, he blames Roxy for leaving the keys in the door, but then the penny drops, and Ronnie knows she's been busted.
When the penny drops as to Ross's guilt, she's understandably not so keen to stick around Emmerdale and play mummy to her little darlings.