What does moon mean?
The moon is the natural satellite of Earth and the principal object in the sky visible from the planet after the Sun. In broader astronomical usage, a moon is any natural satellite orbiting a planet, so the term can describe bodies beyond Earth’s own satellite. The word also refers to a lunar phase or to the approximately 29.5-day cycle from one new moon to the next, reflecting its central role in the development of calendars. Compounds such as “full moon,” “moonlight,” and “moonshine” show how deeply the Moon is embedded in ordinary language, literature, and folklore. As an informal verb, “to moon” means to expose one’s buttocks, usually as a joke or gesture of contempt. Outside that humorous use, the word carries associations of night, mystery, romance, cycles, and the passage of time.
Earth’s natural satellite, or any natural satellite orbiting a planet or other astronomical body.
"The Moon has influenced human calendars and mythology throughout history."
When the reference is specifically to Earth’s satellite, “the Moon” is normally capitalized in English.
To expose one’s buttocks, especially as a joke, insult, or act of defiance.
"He mooned the camera before the interview ended."
This is informal and often humorous or crude. The expression is especially associated with public or visible gestures.
The plural is used for multiple natural satellites, lunar phases, or units of lunar time; in the verb sense, third-person singular is “moons.”
"The solar system contains many moons."
The Moon is Earth’s only natural satellite, and its light has shaped calendars, tides, folklore, and human timekeeping for millennia.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does moon come from?
The English word comes from Old English mōna, meaning “the Moon,” and is inherited from Proto-Germanic *mēnō. It is cognate with Latin luna, a term that was itself borrowed from Greek Selene, the Greek goddess and personification of the Moon. English developed many compounds from the native word, including “moonlight” and “moonbeam,” while the Latin cognate contributed forms such as “lunar” and “lunatic.”
Related word forms
How moon is actually used
The noun is standard in British and American English. The verb “moon” is informal and often humorous, vulgar, or provocative; it is more common in phrases such as “moon the crowd” than in formal writing.