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  • moon
    moon
    noun
    none the moon or the Moon the earth's natural satellite, orbiting the earth at a mean distance of 238,857 miles (384,393 km) and having a diameter of 2,160 miles (3,476 km).
  • Moon
    Moon
    noun
    Sun Myung 1920–2012, Korean religious leader: founder of the Unification Church.
Synonyms

moon

1 American  
[moon] / mun /

noun

  • moons
    plural
  1. none the moon or the Moon the earth's natural satellite, orbiting the earth at a mean distance of 238,857 miles (384,393 km) and having a diameter of 2,160 miles (3,476 km).

  2. this body during a particular lunar month, or during a certain period of time, or at a certain point of time, regarded as a distinct object or entity.

  3. a lunar month, or, in general, a month.

  4. any planetary satellite.

    the moons of Jupiter.

  5. something shaped like an orb or a crescent.

  6. moonlight.

  7. a platyfish.

  8. Slang. the buttocks, especially when bared.


verb (used without object)

  • moons,
    present (3rd person singular)
  • mooned,
    past participle,  past
  • mooning
    present participle
  1. to act or wander abstractedly or listlessly.

    You've been mooning about all day.

  2. to sentimentalize or remember nostalgically.

    He spent the day mooning about his lost love.

  3. to gaze dreamily or sentimentally at something or someone.

    They sat there mooning into each other's eyes.

  4. Slang. to expose one's buttocks suddenly and publicly as a prank or gesture of disrespect.

verb (used with object)

  • moons,
    present (3rd person singular)
  • mooned,
    past participle,  past
  • mooning
    present participle
  1. to spend (time) idly.

    She mooned the afternoon away, unable to think what to do next.

  2. to illuminate by or align against the moon.

  3. Slang. to expose one's buttocks to as a prank or gesture of disrespect.

idioms

  1. over the moon. see over the moon.

  2. blue moon. see blue moon.

Moon 2 American  
[moon] / mun /

noun

  1. Sun Myung 1920–2012, Korean religious leader: founder of the Unification Church.


Moon 1 British  
/ muːn /

noun

  1. a system of embossed alphabetical signs for blind readers, the fourteen basic characters of which can, by rotation, mimic most of the letters of the Roman alphabet, thereby making learning easier for those who learned to read before going blind Compare Braille 1

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

moon 2 British  
/ muːn /

noun

  1. (sometimes capital) the natural satellite of the earth. Diameter: 3476 km; mass: 7.35 × 10 22 kg; mean distance from earth: 384 400 km; periods of rotation and revolution: 27.32 days

  2. the face of the moon as it is seen during its revolution around the earth, esp at one of its phases

    new moon

    full moon

  3. any natural satellite of a planet

  4. moonlight; moonshine

  5. something resembling a moon

  6. a month, esp a lunar one

  7. very seldom

  8. informal extremely happy; ecstatic

  9. to desire or attempt something unattainable or difficult to obtain

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

verb

  1. to be idle in a listless way, as if in love, or to idle (time) away

  2. slang (intr) to expose one's buttocks to passers-by

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
Moon 3 British  
/ muːn /

noun

  1. William. 1818–94, British inventor of the Moon writing system in 1847, who, himself blind, taught blind children in Brighton and printed mainly religious works from stereotyped plates of his own designing

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

moon Scientific  
/ mo̅o̅n /
  1. Often Moon. The natural satellite of Earth, visible by reflection of sunlight and traveling around Earth in a slightly elliptical orbit at an average distance of about 381,600 km (237,000 mi). The Moon's average diameter is 3,480 km (2,160 mi), and its mass is about 1/80 that of Earth. Its average period of revolution around Earth is 29 days, 12 hours, 44 minutes.

  2. See more at giant impact theory

  3. A natural satellite revolving around a planet.


moon Cultural  
  1. A natural satellite of a planet; an object that revolves around a planet. The planets vary in the number of their moons; for example, Mercury and Venus have none, the Earth has one, and Jupiter has seventeen or more. The planets' moons, like the planets themselves, shine by reflected light.


moon More Idioms  

Closer Look

The Earth's Moon is a desolate and quiet place. The only natural satellite of Earth, it consists almost entirely of rock, shows no signs of ongoing geologic activity, has no water, and has a very thin atmosphere consisting primarily of sodium. But our Moon does not present a typical case for planetary satellites. Over the last 50 years, over a hundred more moons have been discovered in the solar system, so that they now total 165, nearly all of them orbiting the larger planets Jupiter, Saturn, and Uranus (Mercury and Venus have no moon), with an additional four moons orbiting dwarf planets. Because they are so far from the Sun, these moons are for the most part extremely cold. Io, one of Jupiter's 63 known moons, is an exception. It is the most geologically active body in the solar system, with almost constant volcanic activity and a surface covered by cooling lava. Some scientists think that another moon of Jupiter, Europa, may have liquid water capable of supporting life underneath a thick layer of surface ice. Titan, one of Saturn's moons, may also be capable of supporting primitive life in the ocean of liquid methane on its frigid surface.

Discover More

The Earth's moon is about 240,000 miles away and is about 2,000 miles in diameter. The volume of the Earth is fifty times that of the moon; the mass of the Earth is about eighty times that of the moon. The moon has no atmosphere, and its gravity is about one-sixth that of the Earth.

Other Word Forms

Derived Forms

Inflected Forms

Nouns

Participles

Conjugated Forms

Present

Past

Future


Etymology

Origin of moon

First recorded before 900; Middle English mone, Old English mōna; cognate with Old High German māno, Old Norse māni, Gothic mena; akin to German Mond “moon,” Latin mēnsis “month,” Greek mḗnē “moon,” Sanskrit māsa “moon, month”


Explanation

Werewolves love to howl at a full moon. The moon is our planet’s satellite, and it rotates around the earth and reflects light from the sun. Also, “to moon” means to show your rear. The moon is out! Giggle giggle. The earth has just one moon, but the word moon can mean any natural satellite of any planet. Astronomers have discovered many moons — there are more than 160 in our solar system alone. Poets have been fascinated by the moon for a long time, and "to moon" also means "to act in a dreamy or aimless way." Our months are marked by changes in the moon's phase, and the Proto-Indo-European root means both "moon" and "month."

Keep Reading on Vocabulary.com

Vocabulary lists containing moon

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

See Examples For:

The print was part of a Nasa project to document the effort of sending the first humans to the moon and is on display as part of the Pop Art at Cartwright Hall exhibition.

From BBC ● Nov. 9, 2026

"The moon is perfect, and yet I only found two little ones last night," Giuseppe Esposito, 69, told AFP as he searched with his dog Attila.

From Barron's ● Nov. 4, 2026

"I was just over the moon, I couldn't be happier," Anthony said.

From BBC ● Nov. 2, 2026

Scientists say this marine heat wave has caused seawater levels to rise 1.25 to 1.8 feet higher than they would just from the movement of the moon, Earth and sun.

From Los Angeles Times ● Oct. 29, 2026

Way off somewhere a dog howled at the moon, and other dogs picked up his wolfish cry.

From "The Teacher’s Funeral" by Richard Peck

Blue Origin is developing a different approach using its Blue Moon Mark 2 lander.

From Science Daily ● Nov. 9, 2026

These efforts are intended to reduce technical risks, accelerate the schedule, and establish the foundation for a lasting American presence on the Moon.

From Science Daily ● Nov. 9, 2026

Both companies are working toward having their systems ready to support a crewed Moon landing in 2028.

From Science Daily ● Nov. 9, 2026

This is because the Moon will be below the horizon around midnight, meaning its reflected light will be less likely to spoil the view.

From BBC ● Nov. 7, 2026

The Old Man of the Moon looked at Haiyi, his black eyes piercing.

From "When the Sea Turned to Silver" by Grace Lin

The school gymnasium was more chaotic, with voters and volunteers, than it has been in many election moons.

From The Wall Street Journal ● Nov. 4, 2026

NASA’s La Cañada Flintridge-based Jet Propulsion Laboratory built this snakelike machine with the goal of one day using it to explore difficult-to-reach places on other planets, moons or asteroids.

From Los Angeles Times ● Oct. 28, 2026

Those future samples could provide another important piece of the puzzle, helping researchers determine how different regions of the early Solar System exchanged material and ultimately produced the planets, moons, and asteroids we observe today.

From Science Daily ● Oct. 24, 2026

One theory for the origin of the moons -- the "giant impact" hypothesis -- is that they formed after a celestial body collided with Mars.

From Barron's ● Oct. 19, 2026

We could see the ring on Saturn, three moons on Jupiter, and the craters on our own moon.

From "Cheaper by the Dozen" by Frank B. Gilbreth Jr. and Ernestine Gilbreth Carey

While accepting the prize, Madonna reminisced about how her manager scolded her backstage at the very first MTV awards show, where she briefly mooned the audience in a performance fumble.

From Barron's ● Sep. 28, 2026

Perkins: What’s so great about this is seeing someone who looks like Lakeith being mooned after.

From Slate ● Nov. 20, 2019

She and Tom Arnold had mooned the crowd at a World Series game to show off their matching tattoos.

From Los Angeles Times ● Apr. 10, 2018

Buffy The Vampire Slayer and its spin-off, Angel, were cult classics, the just-home-from-school fantasy shows that made vampires sexy long before R-Patz and Kristen mooned at each other in Twilight.

From The Guardian ● Jun. 2, 2013

Eddie mooned on down to La Ida and talked to his friend the bartender.

From "Cannery Row" by John Steinbeck

Bogotá’s unorthodox mayor, Antanas Mockus—who rose to fame after mooning student protesters and deployed mimes to control traffic—viewed the activity as a gambit “to achieve self-regulation in the behavior among citizens.”

From Slate ● Dec. 22, 2024

Bad-boy drummer Tommy Lee, known for mooning the audience and for his marriage to Heather Locklear, is a key part of the band’s hardcore image.

From Los Angeles Times ● Feb. 2, 2022

Footage captured the moment a terminally ill man was arrested by police officers after "mooning" at speed camera van.

From BBC ● Nov. 10, 2021

In all honesty, I’m a bit surprised to be mooning over “Terminator 2” in public.

From New York Times ● Jul. 31, 2020

Then she got herself a cup and sat down beside him, her beautiful eyes mooning with pity.

From "Jacob Have I Loved" by Katherine Paterson

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