Amnesty is when a party is pardoned for offenses that it may have committed.
In the context of the law, once amnesty is granted, then the party will not have to face any negative legal consequences for committing the offense that is the subject of the amnesty.
It is common for amnesty to be granted to soldiers of the losing army following a war or revolution. In many such cases, amnesty is granted so that the soldiers do not reconsider taking up arms and continuing the conflict after a formal surrender has been made by the ranking general.
Following the end of the Civil War, for example, amnesty was granted to the Confederate soldiers. This restored their full rights under the Constitution, and helped to resolve the conflict.