A gyro-pilot, or autopilot, is a device that automatically controls an aircraft's flight path. Synonyms for gyro-pilot include automatic pilot, flight control system, or simply pilot. The term "autothrottle" is also used to describe a system that automatically regulates the aircraft's speed. Another synonym, "flight director," refers to a system that provides guidance to the pilot for course headings and altitude changes. In addition, "guidance system" and "navigation system" can be used to describe the technology used in autopilot systems. Regardless of the terminology, all of these synonyms refer to the same essential technology that enables aircraft to fly themselves with little human intervention.