Pronunciation: (yôm kip'ur, yōm, yom; Seph.Heb. yôm' kē-pOOr'; Ashk. Heb. yōm ki'pur),[key] a Jewish high holy day observed on the 10th day of the month of Tishri by abstinence from food and drink and by the daylong recitation of prayers of repentance in the synagogue. Also called Day of Atonement.