前进,航行速度,进展
Headway \Head"way`\, n. 1. The progress made by a ship in motion; hence, progress or success of any kind. 2. (Arch.) Clear space under an arch, girder, and the like, sufficient to allow of easy passing underneath.
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}]