Self-sustainability and self-sufficiency are overlapping states of being in which an entity requires little or no reliance on external sources.[1][2] Self-sufficiency entails the self being enough in fulfilling one's own needs, and a self-sustaining entity can maintain self-sufficiency indefinitely. These states represent types of personal or collective autonomy.[3] A self-sufficient economy, also called an autarky, is one that requires little or no trade with the outside world.