idiom · informal

once in a blue moon

/wʌns ɪn ə ˌbluː ˈmuːn/once·in·a·blue·MOON

speakingtask2

very rarely

Examples

I go to the cinema once in a blue moon, usually when a movie gets great reviews.

Our neighbours visit once in a blue moon, so we catch up when they do.

Once in a blue moon I treat myself to a day off from studying.

Band 8 sentence

I travel abroad once in a blue moon, usually for a special conference or family event.

Collocations

  • go somewhere once in a blue moon
  • happen once in a blue moon

Word family

once in a blue moon idiom

Common mistakes

once in blue moononce in a blue moon

one in a blue moononce in a blue moon

Say it for a higher band

5rarely6hardly ever7+once in a blue moon

Synonyms

rarely

hardly ever

Easily confused

rarely

I rarely eat fast food because I prefer cooking at home.

every now and then

I exercise every now and then when I have time.

Related words

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In Time

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