意味
Something that happens extremely infrequently or almost never.
文化的背景
In the US, the phrase is often associated with the 'Blue Moon' brand of beer, which uses the idiom to suggest their beer is a unique, rare treat. British speakers use this idiom frequently in self-deprecating humor, especially when talking about their own bad habits or lack of exercise. While the idiom is common, scientists avoid it because 'blue moon' has two different astronomical definitions, leading to confusion in technical contexts. The idiom is immortalized in the Great American Songbook. The song 'Blue Moon' has been covered by everyone from Elvis Presley to Frank Sinatra, making the phrase globally recognized.
Use it for self-correction
If you accidentally say you 'never' do something, but then remember you did it once last year, correct yourself with 'Well, once in a blue moon.'
Don't pluralize
Never say 'once in blue moons.' The phrase is always singular.
意味
Something that happens extremely infrequently or almost never.
Use it for self-correction
If you accidentally say you 'never' do something, but then remember you did it once last year, correct yourself with 'Well, once in a blue moon.'
Don't pluralize
Never say 'once in blue moons.' The phrase is always singular.
Pair with 'but'
This idiom works great in contrast: 'I don't usually like horror movies, but once in a blue moon, I'll watch one.'
自分をテスト
Complete the sentence with the correct idiom.
I don't like spicy food, so I only eat chili ______.
The full, correct idiom is 'once in a blue moon.'
Which sentence uses the idiom correctly?
Select the most natural sentence.
Vacationing every five years is a rare event. Brushing teeth and the sun rising are daily events.
Match the situation to the frequency.
If Sarah visits her grandmother once every three years, she visits her...
Once every three years is very infrequent, which fits the idiom.
Complete the dialogue.
A: Do you ever go to the opera? B: ________. It's too expensive for me.
The second sentence explains that it's too expensive, which supports the idea of it being a rare event.
🎉 スコア： /4
ビジュアル学習ツール
練習問題バンク
4 問題I don't like spicy food, so I only eat chili ______.
The full, correct idiom is 'once in a blue moon.'
Select the most natural sentence.
Vacationing every five years is a rare event. Brushing teeth and the sun rising are daily events.
If Sarah visits her grandmother once every three years, she visits her...
Once every three years is very infrequent, which fits the idiom.
A: Do you ever go to the opera? B: ________. It's too expensive for me.
The second sentence explains that it's too expensive, which supports the idea of it being a rare event.
🎉 スコア： /4
よくある質問
4 問No, it's just a name for a second full moon in a month. However, smoke or dust in the air can sometimes make the moon look blue.
Yes, but keep it to semi-formal emails. In a very formal contract, use 'infrequently.'
About every 2.7 years. This is why the idiom means 'very rarely.'
It is always 'in'. Think of the event happening 'within' that rare time period.
関連フレーズ
Hardly ever
synonymAlmost never.
Once in a lifetime
similarSomething that happens only once in a person's life.
When pigs fly
contrastSomething that will never happen.
Few and far between
similarNot happening often.
