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 can damage an aircraft's undercarriage upon landing. Crosswinds, sometimes abbreviated as X/WIND, are reported in knots, abbreviated kt, and often use the plural form in expressions such as "with 40kt crosswinds". Smaller aircraft are often not limited by their ability to land in a crosswind, but may see their ability to taxi safely reduced.