venturi

/vɛnˈtʊri/
noun
  1. A tube or device that narrows in the middle to increase the speed of a fluid (liquid or gas) and decrease its pressure, used in carburetors, flow meters, and pumps.
    • The science teacher showed the class how a venturi creates a vacuum by speeding up airflow.
    • The mechanic checked the venturi in the carburetor for any blockages.
    • A venturi is often used in water treatment systems to mix chemicals efficiently.