A nozzle is a device designed to control the direction or flow of a fluid, such as air or water. It typically has a specific shape that helps to increase the speed of the fluid as it exits. Nozzles are commonly used in various applications, including spray bottles, garden hoses, and jet engines. In engineering, nozzles can be found in many systems, such as rocket propulsion and industrial machinery. They play a crucial role in optimizing performance by directing the flow efficiently, which can enhance processes like cooling, mixing, or propulsion.