An economic union is a high level of cooperation between different countries. It allows for the free movement of goods, services, money, and workers across borders. It also requires member countries to work together on their economic rules and policies through shared organizations.

Key features include:

• The Four Freedoms: Unrestricted movement of goods, services, capital, and labor between members.
• Common trade policy: Unified taxes and agreements when trading with countries outside the group.
• Policy coordination: Countries align their tax, spending, and financial rules.
• Shared institutions: Organizations that can make decisions that apply to all members.
• Common currency: Some unions choose to use the same money, which creates a monetary union.

The goal of an economic union is to make several countries act like one single market. A well-known example is the European Union.