[1] : The Collaborative International Dictionary of English v.0.48

headway \head"way`\ -w^urk`, n.
   1. the progress made by a ship in motion; hence, progress or
      success of any kind.
      1913 webster

   2. arch. clear space under an arch, girder, and the like,
      sufficient to allow of easy passing underneath; clearance;
      headroom.
      1913 webster

[2] : WordNet (r) 2.0

headway
     n 1: vertical space available to allow easy passage under
          something syn: headroom, clearance
     2: forward movement; "the ship made little headway against the
        gale" syn: head
see also:
headroom clearance head 

[3] : Moby Thesaurus II by Grady Ward, 1.0

65 moby thesaurus words for "headway":
   great leap forward, advance, advancement, advancing, amelioration,
   amendment, anabasis, ascent, bettering, betterment, boost, career,
   course, driftway, enhancement, enrichment, eugenics, euthenics,
   forward motion, forwardal, forwarding, furtherance, furthering,
   gain ground, get ahead, get going, go, go ahead, go-ahead,
   improvement, leeway, lift, make headway, march, melioration, mend,
   mending, move forward, ongoing, onward course, passage, pickup,
   preferment, proceed, proficiency, progress, progression,
   progressiveness, promotion, recovery, restoration, revival, rise,
   rolling, rolling on, steerageway, sternway, travel, upbeat, uplift,
   upping, upswing, uptrend, upward mobility, way

Headway >> H Words
Headway, definition of term: Headway
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