A nozzle is a device designed to control the direction or flow of a fluid, typically a gas or liquid. It is commonly used in various applications, such as in spray bottles, fire hoses, and jet engines. By changing the shape of the nozzle, the speed and pressure of the fluid can be adjusted, allowing for more efficient use of the material being expelled. Nozzles come in different shapes and sizes, depending on their specific purpose. For example, a garden hose nozzle can help create a fine mist or a strong jet of water, while a rocket nozzle is designed to maximize thrust by efficiently expelling combustion gases.