noun \ˈmün\

the moon : the large round object that circles the Earth and that shines at night by reflecting light from the sun

: a large round object like the moon that circles around a planet other than the Earth

Full Definition of MOON

a often capitalized :  the earth's natural satellite that shines by the sun's reflected light, revolves about the earth from west to east in about 2912 days with reference to the sun or about 2713 days with reference to the stars, and has a diameter of 2160 miles (3475 kilometers), a mean distance from the earth of about 238,900 miles (384,400 kilometers), and a mass about one eightieth that of the earth —usually used with the
b :  one complete moon cycle consisting of four phases
c :  satellite 2; specifically :  a natural satellite of a planet
:  an indefinite usually extended period of time <a labor of many moons>
:  moonlight
:  something that resembles a moon: as
a :  a highly translucent spot on old porcelain
b :  lunule
c slang :  naked buttocks
:  something impossible or inaccessible <reach for the moon>
moon·like \-ˌlīk\ adjective
over the moon
:  very pleased :  in high spirits

Examples of MOON

  1. The telescope makes the craters on the surface of the moon incredibly clear.
  2. the orbit of the Moon around the Earth
  3. Europa and Io are both moons of Jupiter.
  4. a planet orbited by one moon

Origin of MOON

Middle English mone, from Old English mōna; akin to Old High German māno moon, Latin mensis month, Greek mēn month, mēnē moon
First Known Use: before 12th century

Other Astronomy Terms

gibbous, nadir, nebulous, penumbra, retrograde, sidereal, syzygy, wane, wax, zenith



: to bend over and show your bare buttocks to someone as a rude joke or insult

Full Definition of MOON

transitive verb
:  to spend in idle reverie :  dream —used with away
slang :  to expose one's naked buttocks to
intransitive verb
:  to spend time in idle reverie :  behave abstractedly

Examples of MOON

  1. One of the boys mooned the crowd.
  2. One of the boys mooned at the crowd.

First Known Use of MOON



noun \ˈmün\   (Medical Dictionary)

Medical Definition of MOON

:  lunula a
May 23, 2015
debouch Hear it
to emerge or cause to emerge
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