moon

moon [mo͞on]

n.

[ME mone < OE mona, akin to Goth mēna < IE * mēn-, month, moon (> L mensis, Gr mēn, month, mēne, moon) < base mē-, to MEASURE]

1. [often M-] the celestial body that revolves around the earth from west to east in c. 27¹/ ₃ days with reference to the stars and once in c. 29¹/ ₂ days with reference to the sun, and that accompanies the earth in its yearly revolution about the sun: diameter, c. 3,476 km ( c. 2,160 mi); mean distance from the earth, c. 384,404 km ( c. 238,857 mi); mean density, c. ³/ ₅ that of the earth; mass, c. ¹/ ₈₁; volume, c. ¹/ ₄₉: with the

2. this body as it appears during a particular lunar month or period of time, or at a particular time of the month: see NEW MOON, CRESCENT, HALF-MOON, FULL MOON, OLD MOON, FIRST QUARTER, LAST QUARTER

3. a month; esp., a lunar month

4. MOONLIGHT

5. anything shaped like the moon (i.e., an orb or crescent)

6. any natural satellite; esp., a natural satellite of a planet

vi.

[from the notion of behaving as if moonstruck]

1. to behave in an idle, dreamy, or abstracted way, as when in love

2. [from an earlier slang use of the noun, meaning “buttocks”] Slang to engage in the prank of momentarily baring one's buttocks in public

vt.

1. to pass (time) in mooning

2. Slang to expose one's buttocks to (someone) as a prank

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once in a blue moon

very seldom; almost never