1. reparation for a wrong or injury: "she wanted to make atonement for her husband's behavior"
▪ (in religious contexts) reparation or expiation for sin: "an annual ceremony of confession and atonement for sin"
▪ the reconciliation of God and humankind through Jesus Christ.
Word Originearly 16th century (denoting unity or reconciliation, especially between God and man): from at one + -ment, influenced by medieval Latin adunamentum ‘unity’, and earlier onement from an obsolete verb one ‘to unite’.