From plank + way.
plankway (plural plankways)
- A walkway consisting of a series of planks.
2009 August 2, Christine Muhlke, “Kelp Wanted”, in New York Times[1]:Unlike other farms, theirs exists in a dim, tidal underworld: barnacle- and starfish-covered pilings hold up a few narrow wooden plankways for the abalone harvesters.