A simplified definition though it is way more complex and deep than just this.
Forgiveness is based on mercy.
Justice demands a payment and mercy says forgiveness can be made by accepting a payment of either sacrifice or Jesus perfect payment.
Reconciliation is based on grace.
Reconciliation builds upon forgiveness and restores the relationship.
2 Corinthians 5:20 NIV
We are therefore Christ’s ambassadors, as though God were making his appeal through us. We implore you on Christ’s behalf: Be reconciled to God.
1 Peter 2:9 NIV
But you are a chosen people, a royal priesthood, a holy nation, God’s special possession, that you may declare the praises of him who called you out of darkness into his wonderful light.
1 Peter 2:10 NIV
Once you were not a people, but now you are the people of God; once you had not received mercy, but now you have received mercy.
