A vehicle that carries people through space. Notice the 'ship' part — a spaceship is imagined as something people live inside and travel in for a long way, with a crew, rooms, doors, a captain. That is why the word belongs mostly to stories: films, cartoons, science fiction, children's drawings. When scientists talk about real machines, they usually say 'spacecraft' (which covers machines with nobody inside as well) or the specific name — 'the shuttle', 'the capsule', 'the rocket'. NASA does not send up 'spaceships'. So the word carries a feeling of imagination and adventure that 'spacecraft' does not. Adults use it happily when they are being playful, or when talking to children, or about films. There is also a common everyday use where a spaceship means the round flying machine aliens arrive in — the 'flying saucer' shape. And computer programmers call the <=> symbol the 'spaceship operator', because it looks like that saucer seen from the side.