(n)(Judaism) a solemn and major fast day on the Jewish calendar; 10th of Tishri; its observance is one of the requirements of the Mosaic law, Syn.Day of Atonement
The Collaborative International Dictionary of English (GCIDE) v.0.53Collaborative International Dictionary (GCIDE)
[ Heb. yōm kippūr, day of atonement. ] (Jewish Antiq.) the only fast day of the Mosaic ritual, celebrated on the tenth day of the seventh month (Tishri), according to the rites described in Leviticus xvi. Also called Day of Atonement. [ Webster 1913 Suppl. +PJC ]