once in a blue moon

Idiom Definition

Idiom Definition - once in a blue moon

"once in a blue moon"

to happen very rarely


Related words and phrases:

Idiom Scenario 1

Idiom Definition - once in a blue moon

Two friends are talking ...

Friend 1:  Wow! You're really looking good. Have you been dieting?

Friend 2:  Thanks.  Yes, I've been on a diet for almost a year now.

Friend 1:  You used to love fast food so much. Don't you miss it?

Friend 2:  It's not a totally radical diet.  I allow myself fast food once in a blue moon.

Friend 1:  So, how many times have you been through the drive-thru in the last year?

Friend 2:  Once.

Idiom Scenario 2

Idiom Definition - once in a blue moon

Two colleagues are talking ...

Colleague 1:  Does your company have casual Friday's?

Colleague 2:  No, not really. The dress code is always business, except, every once in a while, the boss will declare a Friday before a long weekend as casual.

Colleague 1:  So you would say that you can wear jeans to work only once in a blue moon?

Colleague 2:  Exactly.

once in a blue moon - Usage:


Usage Frequency Index:   551   click for frequency by country

once in a blue moon - Gerund Form:

There is no gerund form for once in a blue moon.

once in a blue moon - Examples:

1)  ... trash heap before posting. I do read their messages; once in a blue moon they have something useful to say. 

2)  Sure, serial non-paying down-loaders might just occasionally (once in a blue moon) pay to download music from iTunes or Bandcamp.

3)  ... twice a year, I'll buy a lotto ticket. Once in a blue moon, I'll read my horoscope and chat up a friend about ...

4)  The saying "once in a blue moon" refers to something that's exceedingly rare.

5)  ... and evokes the sense of those brief joyous moments that happen once in a blue moon that person spends the rest of their days revising ...

6)  ... many sea creatures washing up on the beach it is like once in a blue moon. With that whole beaching incident it is very odd that all those whales were ...

7)  And doesn't the phrase "once in a blue moon" indicate something precious and rare?

8)  ... or workshop is not to expect success every time but only once in a blue moon

9)  This is a very rare phenomenon, occurring literally once in a blue moon.

10)  I'll continue to jog once in a blue moon -- but I'm no longer the cardio queen. 

11)  ... but if you buy something durable & only use it once in a blue moon, but it lasts forever, ...

12)  ... sale. Ladies be on watch - this only comes around once in a blue moon!

13)  ... bag, you were also fighting Joe Shmo, who travels once in a blue moon and has no idea how to respect the unwritten rule of airline travel.

14)  ... treat yourself to a soda or fries or whatever. Treats once in a blue moon won't kill you.

15)  ... are few and far between and community-recycling drives are only offered once in a blue moon, if at all.

16)  I rarely eat grains - maybe some rice once in a blue moon, but mostly because I'm not a huge fan of carbs.

17)  ... on a regular basis, don't send an email blast once in a blue moon, rather set a schedule to every an email blast once quarter or each month.

18)  ... those things occasionally work. Every once in a blue moon.

19)  If what you do is rare or openings come up once in a blue moon, you may be at this awhile.

20)  This is a very rare, "once in a blue moon" type of thing. The only previous time this had occurred was during World War II.