A Note from a young friend of the Justice Foundation website. See his letter underneath reply. The ancient Latin phrase is suum cuique. An injustice means that something that belongs to someone, has it withheld or taken away from him. To bring about a state of justice is to reinstate a person in the possession or dominion of his thing.
Restitution occurs when what is owed is repaid in one form or another.
This is also the case for natural rights. Something is owed another human being by the very fact that they are human. The first and foremost is the right to life. I hope this helps.