Advancement or progress.
Promotion.
The act of furthering or helping forward
Movement ahead or forward.
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.
Forward motion, or its rate.
A cross-heading.
The clearance beneath an object, such as an arch, ceiling or bridge; headroom.
Progress toward a goal.