If you're chilly, you might close a window that's letting in a draught. Draught is the British spelling of the word draft.
The noun draught is pronounced exactly like draft, and it also shares most of the same meanings. A cold burst of wind, a swig or a serving of a drink, the act of pulling a heavy load, and the depth of a ship below the surface of the water: each of these can be called a draught. It's easy to confuse the British draught with drought, which means "a shortage of rainfall" and rhymes with "out."