Definition: A device that's used in many electronic fuel injection systems for measuring the volume of air entering the engine. Some use a spring-loaded vane while others use a hot wire or heated filament to sense air flow.

Related Resources:

Making Sense of Sensors: Part 1
There are a lot of things going on in your engine as you drive. A lot of information is taken in and processed. But how is this information gathered and what happens to it once it's collected?

Making Sense of Sensors: Part 2
There are a lot of things going on in your engine as you drive. A lot of information is taken in and processed. But how is this information gathered and what happens to it once it's collected?