once in a lifetime

US /wʌns ɪn ə ˈlaɪfˌtaɪm/
UK /wʌns ɪn ə ˈlaɪfˌtaɪm/
"once in a lifetime" picture
1.

once in a lifetime, eenmalig

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.
Het zien van de totale zonsverduistering was een once in a lifetime ervaring.
This opportunity to travel the world is truly a once in a lifetime chance.
Deze kans om de wereld rond te reizen is echt een once in a lifetime kans.