The force exerted by the weight of a column of air on a surface is called air pressure.

Here's why:

* Weight: Air, like all matter, has weight due to gravity.

* Column: The air above a surface forms a column that extends all the way to the top of the atmosphere.

* Force: The weight of this column of air exerts a downward force on the surface.

* Pressure: Pressure is defined as force per unit area. Since the weight of the air column acts over the area of the surface, we call this force air pressure.