Trading blocs, common markets, and economic unions are all forms of regional integration that aim to promote economic cooperation and integration between countries in a particular region.

Trading blocs refer to a group of countries that agree to reduce or eliminate trade barriers, such as tariffs and quotas, between themselves. The most common type of trading bloc is a free trade area, where member countries agree to eliminate tariffs on goods traded between them, but maintain their own individual trade policies with non-member countries. Examples of trading blocs include the North American Free Trade Agreement (NAFTA) and the Association of Southeast Asian Nations (ASEAN).

Common markets go beyond free trade areas by allowing the free movement of goods, services, capital, and labor between member countries. In addition to eliminating trade barriers, common markets typically involve the harmonization of economic policies and regulations between member countries. The European Union (EU) is an example of a common market.

Economic unions are the most advanced form of regional integration, involving not only the free movement of goods, services, capital, and labor, but also the coordination of economic policies and institutions, such as a common currency and central bank. The EU is also an example of an economic union, with the euro as its common currency and the European Central Bank as its central bank. Other examples of economic unions include the East African Community and the Union of South American Nations.