[1] : The Collaborative International Dictionary of English v.0.48

moon \moon\ m=oon, n. oe. mone, as. m=ona; akin to d.
   maan, os.  ohg. m=ano, g. mond, icel. m=ani, dan. maane,
   sw. mane, goth. m=ena, lith. menu, l. mensis month,
   gr. mh`nh moon, mh`n month, skr. m=as moon, month; prob.
   from a root meaning to measure cf. skr. m=a to measure,
   from its serving to measure the time. root271. cf. mete
   to measure, menses, monday, month.
   1. the celestial orb which revolves round the earth; the
      satellite of the earth; a secondary planet, whose light,
      borrowed from the sun, is reflected to the earth, and
      serves to dispel the darkness of night. the diameter of
      the moon is 2,160 miles, its mean distance from the earth
      is 240,000 miles, and its mass is one eightieth that of
      the earth. see lunar month, under month.
      1913 webster

            the crescent moon, the diadem of night. --cowper.
      1913 webster

   2. a secondary planet, or satellite, revolving about any
      member of the solar system; as, the moons of jupiter or
      saturn.
      1913 webster

   3. the time occupied by the moon in making one revolution in
      her orbit; a month; as, it's been many moons since i last
      visited washington. --shak.
      1913 webster

   4. fort. a crescentlike outwork. see half-moon.
      1913 webster

   5. the deliberately exposed naked buttocks. slang
      pjc

   moon blindness.
      a far. a kind of ophthalmia liable to recur at
          intervals of three or four weeks.
      b med. hemeralopia.

   moon dial, a dial used to indicate time by moonlight.

   moon face, a round face like a full moon.

   moon madness, lunacy. poetic

   moon month, a lunar month.

   moon trefoil bot., a shrubby species of medic medicago
      arborea. see medic.

   moon year, a lunar year, consisting of lunar months, being
      sometimes twelve and sometimes thirteen.

   blue moon, see blue moon in the vocabulary.

   many moons, a long time.
      1913 webster
see also:
mete menses monday month lunar month half-moon 
moon blindness moon dial moon face moon madness moon month 
moon trefoil medicago arborea medic moon year blue moon 
many moons 

Moon >> M Words
Moon, definition of term: Moon
moon_pag1.html

Madness >> M Words
Madness, definition of term: Madness
madness_pag1.html

Harvest Moon >> H Words
Harvest Moon, definition of term: Harvest Moon
harvest+moon_pag1.html

Full Moon >> F Words
Full Moon, definition of term: Full Moon
full+moon_pag1.html

Blue Moon >> B Words
Blue Moon, definition of term: Blue Moon
blue+moon_pag1.html