What does the phrase, "Once in a blue moon", mean?

Question

Just curious

Answer 1

Once in a blue moon - is a idiom and it means -
Rarely, once in a very long time, as in We only see our daughter once in a blue moon. This term is something of a misnomer, because an actual blue moon--that is, the appearance of a second full moon in the same calendar month--occurs every 32 months or so. Further, the moon can appear blue in color at any time, depending on weather conditions. [Early 1800s]

Once In A Blue Moon is also mathematically defined as 1.16699016 × 10-8 hertz, since a blue moon occurs every 2.71542689 years.-

Answer 2

Selah is correct. That saying describes something that does not occur very often. A 'blue moon' is the second full moon in a calendar month, something that only happens now and then. H ADDENDUM: You are getting a lot of confusing answers for a simple question. The simple explanation is that a 'blue moon' is an expression for something that seldom occurs. A blue moon is the second full moon in a calendar month. May 31, 2007 was the date of the last blue moon. The rare phenomenon of two blue moons occurring in the same year happens approximately once every 19 years. 1999 was the last time a blue moon appeared twice and this was during in January and March. I was lucky enough to see both. Of course, anytime the moon just happens to appear 'blue' due to atmospheric condition, that can also be called a "blue moon." In my lifetime I have never seen this happen and I doubt that any poster here has. The 'other' explanation for a blue moon is when there are four full moons during a growing season; the third full moon is called a "blue moon." The last time that happened was in 2005. H

Answer 3

once in a great long while.

Meaning

A very rare event.

Origin

A blue moon was originally cited as something impossible and later came to mean unlikely. There are rare examples of the moon actually appearing blue, after volcanic eruptions or unusual weather conditions. Another possible derivation is from The Maine Farmers' Almanac. When there were two full moons in a calendar month the first was printed in red, the second in blue.

Answer 4

Of course it means something that happens very infrequently. I have heard two different definitions of the term Blue moon, and one is the second full moon in a calendar month, and the other is the fourth full moon in a calendar quarter, both of which are rather infrequent. The former definition is the more widely quoted, but the second is more likely to be correct, since it dates to medieval times.

Answer 5

Something that is rare and does not happen often.

Usage: I drink once in a blue moon.
This means I drink very rarely.

Answer 6

it means very rarely--or only once in awhile--it is based on how often a blue moon occurs--a blue moon is when there are 2 full moons in a single month--the senond full moon is called a blue moon--since this doesn't happen often--saying once in a blue moon means saying--very rarely...

Answer 7

Rarely.

Answer 8

It means once in a while...a rare occasion.

Answer 9

It happens occasionally; once in a while; not frequent; rarely.

Answer 10

Not often
sometimes
rarely
slim chance
hardly
grave happening
slight chance