noun
: a period that equals the mean time of the moon's revolution from any point of the ecliptic back to the same point and amounts to 27 days, 7 hours, 43 minutes, and 4.7 seconds of mean solar time
noun
: a period that equals the mean time of the moon's revolution from any point of the ecliptic back to the same point and amounts to 27 days, 7 hours, 43 minutes, and 4.7 seconds of mean solar time
Webster's New International English Dictionary. Новый международный словарь английского языка Webster. 2012