Final answer:
MS stands for Member States and refers to countries that are members of specific regional boards or international organizations.
Step-by-step explanation:
MS, which stands for Member States, is a term often used in the context of global governance and international organizations, such as the United Nations. It refers to the countries that are members of a specific organization or regional board. Without more specific information, it is not possible to determine which regional board or organization the question is referring to. Some examples of regional boards that countries can participate in and accept include the African Union, European Union, ASEAN (Association of Southeast Asian Nations), and many others.