What is the designation for a city that has a population exceeding one million?

The designation for a city that has a population exceeding one million is typically referred to as a "Millionaire city." This term specifically describes urban areas that have reached this population milestone, highlighting their significance in terms of size and the challenges and opportunities that come with large populations.

In contrast, other terms listed have different meanings. A megalopolis generally refers to a chain of roughly adjacent metropolitan areas that have grown together, rather than an individual city surpassing one million. A global city is a larger term that encompasses cities playing significant roles in global economic systems, often addressing aspects like finance, culture, and political influence, and these cities are not exclusively defined by population size alone. Lastly, a metropolitan area refers to a region that includes a city and its surrounding suburbs or closely linked areas, which may encompass several cities or towns but does not specifically define a single city based on its population.