Downrange is the horizontal distance travelled by the spacecraft. When a spacecraft reaches low earth orbit, it is generally downrange about nine hundred kilometers ( nine hundred thousand meters ). The downrange when reaching orbit will decrease as the starting velocity increases. The downrange when reaching orbit will increase as the acceleration decreases. So a low acceleration spaceplane will be far downrange when reaching orbit, while a high thrust rocket will be relatively close to the launch place when reaching orbit.
 

This is used in the trajectory tables in atmospheric spacecraft, multi stage spacecraft, and spacecraft cost.
 
  Spacecraft