Noun
The period of a synodic revolution of the moon, or the time from one new moon to the next; varying in length, at different times, from about 29/ to 29/ days, the average length being 29 d., 12h., 44m., 2.9s.
Source: Webster's dictionaryA lunation or synodic month is the mean (average) time from one new moon to the next. Source: Internet
The next approximation (arising from continued fractions) after the Metonic cycle (such as a 334-year cycle) is very sensitive to the values one adopts for the lunation (synodic month) and the year, especially the year. Source: Internet
Hipparchus confirmed this value for the lunation length. Source: Internet
In the J2000.0 epoch, the average length of a lunation is 29.530588 days (or 29 days, 12 hours, 44 minutes, and 3 seconds). Source: Internet
The Hebrew Lunation Number is the count of lunations in the Hebrew calendar with lunation 1 beginning on October 7, 3761 BC. Source: Internet