once in a lifetime
01
used for referring to a very special opportunity that most likely will not be offered more than once to someone
Idiom
例
They experience moments that happen only once in a lifetime.
He feels that this chance only comes once in a lifetime.
once-in-a-lifetime
01
一生に一度の, 特別な
extremely rare or unique and is not likely to be repeated or experienced again in one's lifetime
例
Being able to attend the Olympics in person is a once-in-a-lifetime opportunity for most people.
オリンピックに直接参加できることは、ほとんどの人にとって一生に一度の機会です。
Being part of the Commonwealth Games has been a once in a lifetime experience.
コモンウェルスゲームズに参加することは、一生に一度の経験でした。
