1) Air current 2) Current of air 3) Wind 
Wind perpendicular to the motion of the aircraft. The crosswind leg is also one of the many words describing the approach segments. See Final for a diagram.
A crosswind is any wind that has a perpendicular component to the line or direction of travel. In aviation, a crosswind is the component of wind that is blowing across the runway, making landings and take-offs more difficult than if the wind were blowing straight down the runway. If a crosswind is strong enough it may exceed an aircraft`s crosswi....
(from the article `airport`) ...must be considered up to about 15 km (10 miles) from the runways. Runway configurations must also ensure that, for 95 percent of the time, ...
Wind that comes from the side. Bad news for riders!
[n] - wind blowing across the path or a ship or aircraft
Any wind that is blowing perpendicular to a line of travel. 
noun wind blowing across the path or a ship or aircraft
Wind that comes from the side. Bad news for riders!