Definitions:
- a month of approximately 29.53 days, measured from a lunar phase until the return of that same phase. On average, the number of days between Full Moons is about 29.5306 days. The actual number of days may differ from the average number by more than a half day. From one Full Moon to the next, the number of days in one lunation can vary between 29.272 and 29.833 days.
- The irregular period from one new moon until the next.