# once in a blue moon

Pronunciation: say "wuns in uh bloo MOON" US /ˌwʌns ɪn ə ˌblu ˈmun/, UK /wʌns ɪn ə bluː muːn/; AUS say "WUNS in uh bloo MOON" /wʌns ɪn ə bluː muːn/

## Idiom

1. Very rarely; only on unusually infrequent occasions.
   - Simple: Very rarely: only every now and then, almost never.
   - _Once in a blue moon, she treats herself to an expensive dinner downtown._
   - _The old theater hosts a live performance only once in a blue moon these days._

## Origin

The phrase derives from "blue moon" and first appears in use around 1833.

Source: DictionaryAI, https://dictionaryai.com/define/once-in-a-blue-moon (written from Wiktionary data, CC BY-SA 4.0: https://creativecommons.org/licenses/by-sa/4.0/).