A curved, bow-shaped window space projecting outward from the main walls of a building, similar to a bay window.
The clearance beneath an object, such as an arch, ceiling or bridge; headroom.
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.
Movement ahead or forward.
Forward motion, or its rate.
A cross-heading.
Progress toward a goal.