Principal cities is a term used to describe the largest and most significant cities in a particular region. However, there are many other synonyms that can be used to describe these cities. For example, metropolises, urban centers, major cities, key cities, and hubs are all phrases that can be used to describe principal cities. These cities are often the economic and cultural centers of a region, and they play a crucial role in shaping the area's overall identity. Understanding the different synonyms for principal cities is important when studying geography or urban planning. By using a variety of terms to describe these cities, we can gain a better understanding of their importance and the role they play in shaping communities and regions.