moon

¹moon

noun \ˈmün\

Definition of MOON

1

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 29¹⁄₂ days with reference to the sun or about 27¹⁄₃ 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

2

: an indefinite usually extended period of time <a labor of many moons>

3

: moonlight

4

: something that resembles a moon: as a : a highly translucent spot on old porcelain b : lunule c slang : naked buttocks

5

: 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

Related to MOON

Synonyms: aeon (or eon), blue moon, coon's age, cycle, donkey's years [chiefly British], eternity, forever, long, months, age

Related Words: infinity; lifetime

Near Antonyms: flash, instant, jiffy, minute, moment, second, shake, split second, trice, twinkle, twinkling, wink; microsecond, nanosecond

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Other Astronomy Terms

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