Return to the home page.

Expand/collapse menu.

Visit Our Sites

Unabridged Dictionary

Learner's Dictionary

Word Central for Kids

Expand/collapse menu.

Premium Services

Unabridged Dictionary

Encyclopedia Britannica

Institutional Subscriptions

Expand/collapse menu.

Expand/collapse menu.

Word of the Day

Subscriber Help

Expand/collapse menu.

More Word Games

Daily Crosswords

Expand/collapse menu.

Open Dictionary

Alphabetical Browse

Browse Categories

Submit an Entry

Expand/collapse menu.

Spelling Bee Hive

Hive Headquarters

Spelling Champion

Spelling Reform

Expand/collapse menu.

Word for the Wise

Today's Broadcast

Expand/collapse menu.

Books and CD-Roms

Online Services

Palm and Pocket PC

Expand/collapse menu.

Looking Up a Word

Citing the Dictionary

Audio Pronunciations

Word Games Help

Expand/collapse menu.

Merriam-Webster FAQ

Advertising Info

Copyright Notice

Hooked Media

Flash Player Required

The Adobe Flash Player is required in order to view this content. You can get it here:

moons

Browse the Dictionary:: A; B; C; D; E; F; G; H; I; J; K; L; M; N; O; P; Q; R; S; T; U; V; W; X; Y; Z; #

blue moon

Main Entry: blue moon

Function: noun

Date: 1821

1 : a very long period of time —usually used in the phrase once in a blue moon <such people happen along only once in a blue moon — Saturday Review>
2 : a second full moon in a calendar month

Learn more about "moons"

Learn more about "moons" and related topics at Britannica.com

Pronunciation Symbols