1. Agreement; concord; reconciliation, after enmity or controversy. Romans 5:11.
Between the Duke of Glo’ster and your brothers.
2. Expiation; satisfaction or reparation made by giving an equivalent for an injury, or by doing or suffering that which is received in satisfaction for an offense or injury; with for.
And Moses said to Aaron, go to the altar, and offer thy sin-offering, and thy burnt-offering, and make an atonement for thyself and for the people. Leviticus 9:7.
When a man has been guilty of any vice, the best atonement he can make for it is, to warn others not to fall into the like.
The Phocians behaved with so much gallantry, that they were thought to have made a sufficient atonement for their former offense.
3. In theology, the expiation of sin made by the obedience and personal sufferings of Christ.
–from the Webster’s Dictionary 1828 Edition