headway

noun

1. 1

   Movement ahead or forward.

2. 2

   Forward motion, or its rate.

3. 3

   The interval of time or distance between the fronts of two vehicles (e.g. buses) moving in succession in the same direction, especially along the same pre-determined route.

4. 4

   Progress toward a goal.

5. 5

   The clearance beneath an object, such as an arch, ceiling or bridge; headroom.

6. 6

   (coal-mining) A cross-heading.