Exhaust velocity refers to the speed at which gases exit a propulsion system, such as a rocket engine. There are several synonyms for this term, including exhaust speed, exhaust flow rate, and thrust velocity. Other related terms include specific impulse and thrust-to-weight ratio. Specific impulse is a measure of how efficiently a propulsion system uses fuel, while thrust-to-weight ratio compares the amount of thrust generated by an engine to the weight of the vehicle it is powering. These terms are important for engineers and scientists working in the field of aerospace, as they help to quantify the performance of rocket engines and other propulsion systems.