Merriam-Webster's Collegiate® Dictionary, 11th Edition
MOON
I. noun
Etymology: Middle English mone, from Old English mōna; akin to Old High German māno moon, Latin mensis month, Greek mēn month, mēnē moon Date: before 12th century
1. the earth's natural satellite that shines by the sun's reflected light, revolves about the earth from west to east in about 29 1/2 days with reference to the sun or about 27 1/3 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, one complete moon cycle consisting of four phases, satellite 2, an indefinite usually extended period of time , moonlight , something that resembles a moon: as, a highly translucent spot on old porcelain, lunule , naked buttocks, something impossible or inaccessible , moonlike adjective
II. verb
Date: 1836
transitive verb to spend in idle reverie ; dream , to expose one's naked buttocks to, intransitive verb to spend time in idle reverie ; behave abstractedly