Definition
A specially shaped tube or passage that narrows in the middle and then widens again. As a fluid (air or liquid) flows through the narrow section, its velocity increases and its static pressure decreases. This pressure drop is used in aircraft systems to draw fuel into an airstream, operate gyroscopic instruments, or measure airflow.
Plain English
A tube with a pinched middle. When air or liquid flows through the pinched part, it speeds up and the pressure drops. That pressure drop can be used to suck fuel in, spin instruments, or measure flow.
Context Anchor
Seen in powerplant and fuel-system discussions where airflow or fuel flow is controlled by a narrowed passage.
Derivation
Named after Giovanni Battista Venturi, an 18th-century Italian physicist who studied how fluids behave when forced through a constricted passage. Knowing the name is tied to a real person helps explain why the term is capitalized in some texts and why it refers to a specific shape, not a general idea.
Why Pilots Care
The venturi effect is the working principle behind float-type carburetors. Understanding it explains how fuel gets pulled into the airstream and why icing in the venturi can choke off engine power even in warm weather.
Analogy
Think of a garden hose: when you squeeze the end to make the opening smaller, the water speeds up and shoots farther. A venturi does the same thing inside a tube — narrower section, faster flow, lower pressure.
Intuition Check
Do not read “venture” here as “a risky trip or undertaking.” In this powerplant context, it is likely a mistaken form of “venturi,” which describes a flow effect, not an action or journey.
Example Sentence 1
Fuel is drawn into the carburetor's airstream by the low pressure created in the venturi.
Example Sentence 2
Older manuals sometimes spelled venturi as venture when describing the low-pressure zone used to draw fuel into the airstream.