forward movement; progress in a forward direction: The ship's headway was slowed by the storm.
2.
progress in general: headway in a career.
3.
rate of progress: a slight headway against concerted opposition.
4.
the time interval or distance between two vehicles, as automobiles, ships, or railroad or subway cars, traveling in the same direction over the same route.
—Idiom
5.
make headway, to proceed forward; advance; progress.
Also called headway.clear vertical space, as between the head and sill of a doorway or between the ceiling and floor of an attic room at a certain point, esp. such height as to allow passage or comfortable occupancy.
[hed-wey] 
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