OriginFrom Ancient Greek σάρος (sáros), from Akkadian 𒊹 (šar₂ /šār/, “3600, total, many, a great quantity or measure”).
The modern astronomical usage is attributed to Edmond Halley, who based it on the word σάρος, defined in the Suda as "a measure and a number among Chaldeans. For 120 saroi make 2222 years according to the Chaldeans' reckoning, if indeed the saros makes 222 lunar months, which are 18 years and 6 months."
- A quantity of 3600, such as 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.
“Suidas’ system (the lunar system) is as follows: reckoning a round 30 days per lunar month, 1 saros ... = 222 lunar months ... rather than 3600 years, as in the solar system, the neros ... being one s”
Formssaroses(plural) · saroi(plural) · Saros(alternative)