Jewish holiday, 1854, from Mishnaic Hebrew yom kippur (in Biblical Hebrew, yom kippurim), literally "day of atonement," from yom "day" + kippur "atonement, expiation."

also shophar, ram's horn blown on Rosh Hashanah and Yom Kippur, 1833, from Hebrew shophar "ram's horn," related to Arabic sawafiru "ram's horns," Akkadian shapparu "wild goat."