once in a lifetime
US /wʌns ɪn ə ˈlaɪfˌtaɪm/
UK /wʌns ɪn ə ˈlaɪfˌtaɪm/
1.
一生に一度の, 千載一遇の
an event or opportunity that is very rare and unlikely to happen again in a person's life
:
•
Seeing the total solar eclipse was a once in a lifetime experience.
皆既日食を見るのは一生に一度の経験だった。
•
This opportunity to travel the world is truly a once in a lifetime chance.
世界を旅するこの機会は、まさに一生に一度のチャンスだ。