Definition of the penny drops
- I had to explain it to him three times, but finally the penny dropped.
: a monetary unit of the United Kingdom formerly equal to ¹/₂₄₀ pound but now equal to ¹/₁₀₀ pound
: a similar monetary unit of any of various other countries in or formerly in the Commonwealth of Nations — see pound at Money Table
: a coin representing one penny
: being a (designated) nail size
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