The sick feeling you get because you are travelling in a car. Your head may spin, your stomach feels wrong, and some people have to stop and throw up. Children get it more than grown-ups, especially if they sit in the back and look down at a book or a phone. Looking out at the far road often helps. It is the same kind of trouble as seasickness, only the moving room is a car, not a boat. In speech people usually say “I get carsick”; carsickness is the noun you use when you name the problem. A doctor may say motion sickness to cover cars, boats, and planes together, but carsickness is the ordinary word for the car.