A more thorough explanation:

Definition: A colony is a territory that is controlled by an independent country, but is considered part of that country for relations with other countries. It can also refer to a group of people who live in a new territory but still have ties to their original country.

Examples:

• The United States was once a colony of Great Britain.
• Puerto Rico is a current colony of the United States.
• The British established colonies in India during the 19th century.

The examples illustrate how a colony is a territory that is controlled by another country. The United States was once a colony of Great Britain, meaning that it was under British control. Puerto Rico is currently a colony of the United States, meaning that it is under American control. The British also established colonies in India, meaning that they controlled parts of India.