The Penny drops - origin of saying?

It is a bit of British slang I don’t understand the origin of.

It (The Penny’s Dropped) means “Ahh! now I get it/I understand now/what was cloudy is now clear”.

Any guesses as to the origin of this saying?


According to “Take Our Word For It”:


Ever put a coin in a gumball machine and it doesn’t go? You jiggle the knob or whack the machine and it drops and you get your merchandise.

Edit: Or what Q.E.D. said.

Ah… Thank you all!

Ignorance once again wrestled to the ground in speedy, efficient fashion!