A torque converter is a type of fluid coupling that is used in automatic transmission systems. It helps transfer torque from the engine to the transmission, and allows the transmission to shift gears more smoothly. However, there are other terms that can be used to refer to a torque converter, such as fluid drive, hydraulic coupling, and fluid clutch. Each of these terms describes the same type of device that is used in automatic transmission systems, and they all serve the same purpose - to help provide smooth power transfer between the engine and the wheels. Regardless of the terminology used, torque converters remain an essential component of modern vehicles.