Callipic cycle: A lunar cycle noted by Callippus in 325 BC which included 4 19-year Metonic cycles. The 940 months had 29 or 30 days each, for a total of 27,759 days.

Hipparchic cycle: Four Callipic cycles less a day, in which days are very nearly 3760 months.

Metonic cycle: 19 year cycle corresponding the 235 lunar months, over which phases of the moon almost land on the same dates of the year. This cycle was the basis for the Greek calendar.

octaeteris:

Saros cycle: The period after which the pattern of lunar and solar eclipses repeat, 18 years and 11 days.

sidereal period: The period for the Moon to complete a revolution relative to the fixed stars, 27.322 days.

synodic period: The period for the Moon to complete a revolution relative to the Earth-Sun line. This is the period for lunar phases as seen for Earth, called the month, and taking 29.53 days for one phase cycle.

Callipic Cycle, Hipparchic Cycle, Metonic Cycle, Month, Moon, Octaeteris