City, a large or important town. Cities are the commercial, industrial, financial, political, and cultural centers of a nation. A city provides opportunities for jobs and offers many cultural and recreational advantages—museums, symphony orchestras, theaters, major sports events. On the other hand, cities tend to be crowded, noisy, and dirty, and have a high crime rate. It generally costs more to live in a city than in a small town, but wages are usually higher.

Not all cities are large. In the United States, it is the form of government, rather than size or importance, that determines whether a community is classed as a city, town, or village. A city is a corporation with a charter granted by the state government. This charter defines its powers and its legal relationship with state and county. Minimum population requirements vary from state to state. Some large communities that qualify as cities choose to remain towns or villages, often for sentimental reasons.

Most large cities are surrounded by suburbs, and it is often difficult to tell where the city ends and the suburbs begin. A city together with its suburbs forms what is usually called a metropolitan area, but this term, as it is generally understood, is not quite the same as the term Metropolitan Statistical Area, used by the United States government (see ). The United Nations Demographic Yearbook uses the term “urban agglomeration.”

Meaningful comparisons of size between large cities are difficult to make because the definition of what constitutes a city varies from country to country. For example, for a while, the only population figure given for Shanghai was 11,859,748, which made it the world's largest city. But that figure was for the shih (municipality) of Shanghai, which has an area of 2,388 square miles (6,185 km 2)and includes vast tracts of open land; the city proper (the densely settled portion) has about the same population as New York City.

In Great Britain and other European countries, the name city is sometimes given as an honorary title to a major community, regardless of its form of government.