seaway

noun

Etymology: From Middle English seewey, from Old English sǣweġ (“a seaway, a path through the sea”), equivalent to sea + way. Compare Saterland Frisian Seegong (“seaway, swell”), German Seegang (“seaway, swell”).

1. A lane or route at sea that is regularly used by ships; a sea lane or trade route.
2. An inland waterway used by seagoing shipping.

   “The coracle […] was a very safe boat for a person of my height and weight, both buoyant and clever in a seaway; but she was the most cross-grained, lop-sided craft to manage.”

3. The headway of a vessel.