Final answer:
An OIG, or Intergovernmental Organization, is a body consisting of member states that cooperate on international issues post World War II, with each state represented by government-appointed delegates.
Step-by-step explanation:
An OIG refers to an Intergovernmental Organization (IGO), which is a group composed of member states united by a formal agreement. Intergovernmental organizations play a significant role in the global arena, particularly since their numbers have surged following World War II. The primary function of IGOs is to facilitate cooperation among nations by addressing international issues and coordinating collective action. This coordination is crucial, especially when the diverse interests of individual states may lead them towards policies that do not align with wider international objectives. Each country in an IGO is represented by delegates selected by their government, ensuring that the nation's interests are voiced during IGO meetings.