air dam

American  

noun

Automotive.

1. a spoiler mounted at the front of an automobile to reduce air flow on the underside of the chassis to increase stability.

---

air dam British  

noun

1. any device, such as a spoiler, that reduces air resistance and increases the stability of a car, aircraft, etc

---

Etymology

Origin of air dam

First recorded in 1970–75

Example Sentences

The Appalachian Mountains often trap the dense, icy air layer, known as a cold air dam, while Atlantic winds usher in a milder air mass that glides up and over the top.

From Washington Post

The highest impact ice event of that winter unfolded Feb. 10-11, with a massive cold air dam that stretched east of the Appalachians from Maine to Georgia.

From Washington Post

There, a stalled frontal boundary enabled milder air to slide up and over the cold air dam.

From Washington Post

The cold air gets trapped against the eastern slopes of the Appalachians, forming a shallow dome of subfreezing air called a cold air dam or wedge.

From Washington Post

The subfreezing air wedge/cold air dam is shown in blue; the milder air wedge is shaded orange.

From Washington Post