An autarky is an economy that does no trade with the outside world and relies entirely on its own resources. It is also referred to as a "closed economy".
An example of a currently run autarky is North Korea.
Where autarky does not exist, a hypothetical assumption of autarky is used to calculate something known as autarkic relative prices.
The word is from the Greek language, where it means self-sufficient. It is sometimes confused with autarchy, which generally means self-government, or government by absolute rule (although autarchy is sometimes also used as a variant spelling of autarky).