Final answer:
The European Union is the cultural region of European nations united for economic purposes, which grew from a trade agreement to a full economic union with common goals including a shared currency, the euro, and the removal of trade barriers.
Step-by-step explanation:
The cultural region comprising a group of European nations unified for economic purposes is called the European Union (EU). This integration began post-World War II with goals such as establishing a closely tied economy to prevent future conflicts. It progressed from a free trade association to a common market, and eventually to a full economic union. The introduction of a common currency, the euro, the elimination of barriers to movement for goods, labor, and capital, and policies aimed at promoting economic stability across member states, represent key steps in the EU's evolution. Notably, the EU has experienced changes such as Britain's decision to leave, known as Brexit, which was completed in January 2020.