MOON, n.
1. The heavenly orb which revolves round the earth a secondary planet or satellite of the earth, whose borrowed light is reflected to the earth and serves to dispel the darkness of night. Its mean distance from the earth Isaiah 60; 1/2 semidiameters of the earth, or 240,000 miles. Its revolution round the earth in 27 days, 7 hours, 43 minutes, constitutes the lunar month.
2. A month. This is the sense in which rude nations use the name of the moon as seven moons.
Half-moon, in fortification, a figure resembling a crescent.