Other forms: rapprochements
Rapprochement is the reestablishment of a happy relationship or arrangement. A peace treaty between warring nations is a kind of rapprochement.
People who usually get along sometimes come into conflict: formerly allied nations go to war, friends feud, and spouses divorce. If a conflict ends and the parties go back to being on good terms, they achieve rapprochement. This term is most often used in international politics — for example, when two countries make peace after a long war, that's rapprochement. The word means "reunion" or "reconciliation" in French, and its root is rapprocher, "to bring near."