the United States of AmericaUˌnited ˌStates of Aˈmerica, the (also the United States, ) (abbrev. the US, the USA) a country in North America, made up of 50 states and the District of Columbia, where the capital is. Population: 316,668,567 (2014). Capital: Washington, D.C. The United States one of the world’s most important industrial nations, and one of its richest countries. With its powerful armed forces, it a military ‘superpower’. The US is often called ‘America.’