The special sealed clothing an astronaut wears in space. It covers the whole body — helmet, gloves, boots, all joined — and it carries its own air, keeps the body at the right pressure and temperature, and blocks the sun's radiation. In other words it is a very small spacecraft shaped like a person, which is why engineers sometimes call it exactly that. Astronauts do not wear it all the time: inside the station they wear ordinary clothes, and the suit goes on for launch, for landing, and for going outside. The word is a normal, plain word — real engineers say it and so do children, which is not true of 'spaceship'. It is used loosely too: a very bulky white protective outfit — for chemicals, for disease, for a clean factory — often gets called a spacesuit by ordinary people, though the technical name is different.