Idin kaciya yana nufin bikin addini na Kirista na tunawa da kaciyar Yesu Kiristi, kamar yadda al'adar Yahudawa ta yi, kwana takwas bayan haihuwarsa. Ana gudanar da wannan bukin ne a ranar 1 ga watan Janairu a kalandar liturgical na wasu darikokin Kirista, kamar cocin Anglican, Lutheran, da Roman Katolika. Kalmar “biki” tana nufin biki ko biki na addini, yayin da “kaciya” na nufin cire kaciyar azzakari ta hanyar tiyatar da ake yi a wasu al’adu da addinai ciki har da addinin Yahudanci.