In the Bible, the word "reconciliation" refers to the restoration of a relationship that has been broken. In the context of Christianity, reconciliation refers to the restoration of our relationship with God through the death and resurrection of Jesus Christ.
When we become Christians, we are reconciled to God. This means that our sins are forgiven, and we are brought into a right relationship with Him. We are also called to be ministers of reconciliation. This means that we are called to help others experience the same forgiveness and reconciliation that we have experienced.