Rural areas are areas which are not towns or cities. They are often farming or agricultural areas. These areas are sometimes called "the country" or "countryside". People who live "in the country" often live in small villages, but they might also live somewhere where there are no other houses nearby.
In the U.S., the United States Census Bureau, defines a "rural area" as sparsely populated and far from urban centers, which make up an estimated 3% of the land area of the U.S., but is home to more than 80% of the total population.