once in a purple moon

English

Etymology

By analogy with once in a blue moon. First use appears c. 1924. See cite below.

Adverb

once in a purple moon (not comparable)

1. (idiomatic) Extremely rarely; almost never.

   Synonyms: see Thesaurus:rarely

   Coordinate term: once in a blue moon

   • 1924, New York Public Library, Dresses - Volumes 10-11, page 15:

     However, in spite all of our complainings, there was a distinct pleasure in shopping along this street, because once in a purple moon, one did strike a really nice model and so very reasonable, that one wondered how the manufacturer could afford to bring it out at the price.

   • 1988, Charles Reynell (publisher), The Economist, Volume 307, Issues 7544-7556, page 11:

     Once in a purple moon, it may be necessary for the top men to settle some awful impasse between themselves.

   • 2012, Robert J. Kravitz, A Collectors Guide to Postage and Fractional Currency, page 20:

     Again, these usually show up in major currency auctions, only once in a purple moon would a dealer have one in stock.

See also

• blue moon