Definitions for "Katabatic wind"
A wind that flows down slopes, usually at night. The air at the top of the slope is cooled a greater amount by radiation than the air lower down, becomes heavier, and flows down the slope under the influence of gravity. The opposite of katabatic is anabatic, applied to a wind blowing up a slope, if it is caused by the convection of heated air.
Any wind blowing downslope. It is usually cold.
a wind that blows down a slope which is strongly cooled after sunset. Given the right topography and surface composition, surprisingly high speeds can be achieved in otherwise light-wind situations.