saros

The period of time, just under 19 years, between successive lunar or solar eclipses occurring when the sun, earth, and moon are in the same positions relative to one another.

A period of 3600 years.

A period of 223 synodic months (approximately 18 years 11 days 8 hours), after which the relative positions of the earth, sun and moon recur, used to predict eclipses.