Colony, a populated area held and governed by an outside country. A colony is a subject territory under the sovereignty (complete control) of the outside country, which may or may not allow some measure of local self-government. Colony also means a group of people who migrate from their homes to another land but remain under the rule of their native country. As individuals, these people are called colonists or colonials.

The rule of an area and its people by another country is called colonialism. The philosophy that underlies the acquisition of colonies is known as imperialism. Colonialism began in ancient times and reached its height in the 19th century. It virtually disappeared in the years following World War II, having been condemned as a moral evil, and only a few colonies—mostly small islands—remain. However, a situation akin to colonialism survives in neocolonialism, where a one-time colonial territory may be dependent on its former colonial ruler or another advanced industrial nation.