“Bottoms up” is a drinking toast. The most direct explanation is simple: if you empty your cup, the bottom of the cup ends up pointing upward. From that image, the phrase came to mean drink up or finish your drink.
That explanation fits the way English often turns a visible action into an expression. In a toast, someone says it just before everyone drinks. For example, a host might raise a glass and say, Bottoms up, meaning everyone should take a drink right away.
A more dramatic story is often repeated: in some versions, dishonest publicans supposedly hid the King’s shilling in the bottom of a beer mug to force men into military service. Once the drinker found the coin, people warned others to check the mug, leading to the phrase. It is memorable, but historians generally treat it as folklore rather than solidly proven origin.
So the safest explanation is this:
- Literal image: the cup’s bottom points up when the drink is finished.
- Common meaning: drink up.
- Famous legend: the coin in the mug tale is widely told, but not well supported.
In short, the phrase is real and common, but the colorful backstory is much less certain.