An Etymological Dictionary of Astronomy and Astrophysics

A → lunisolar calendar used by Jews for religious purposes. The year consists of 12 months alternating between 29 and 30 days, making a year of 354 days.
In order to conform to the → solar year, a → leap month is included every third year. A month
begins the day the new moon is first seen. The years are counted from the time of “creation,” believed by Jewish theologians to have occurred in the year 3761 B.C. Also called → Jewish calendar.

Etymology (EN): Hebrew, from O.E., from O.Fr. Ebreu, from L. Hebraeus, from Gk. Hebraios, from Aramaic ‘ebhrai, corresponding to Heb. ‘ibhri “an Israelite,” literally “one from the other side,” in reference to the River Euphrates, or perhaps simply denoting “immigrant;” from ‘ebher “region on the other or opposite side;” → calendar.

Etymology (PE): Gâhšomâr, → calendar; yahud→ Jewish calendar.