If you guessed that reparation is related to the word repair, you were right. Both come from the Latin word meaning "to restore." While reparation has a range of meanings, they all convey the sense of fixing or making up for a past wrong.
In contemporary usage, the plural form is more common than the singular. Victims of a crime, for example, may receive reparations from the perpetrators. A defeated nation may be forced to pay reparations to its victorious enemies. Many have suggested that the United States government should provide reparations to the descendants of slaves. The word almost always has legal or political connotations, and it conveys the sense of restitution — often expressed in money — for wrongdoing.