Sentence:  They hurried across the waiting hall to the departure gates. Through the windows he could see the floodlights on the field, shining on the <WSD>runways</WSD>. Planes pulled up in rows at the gates, assembly-line style, workers swarming over them like ants even before they stopped. 
Meaning of the word marked with <WSD> tags:  A section of land, usually paved, for airplanes to land on or take off from.