A "shuttle" is a vehicle or device that moves back and forth between two points. In transportation, it often refers to buses or trains that regularly travel between specific locations, such as airports and city centers. These shuttles help people easily reach their destinations without needing personal vehicles. In the context of space exploration, a shuttle refers to the Space Shuttle, a spacecraft used by NASA to transport astronauts and cargo to and from space. The Space Shuttle program operated from 1981 to 2011 and played a crucial role in building the International Space Station and deploying satellites.