'Plank road' definitions:

Definition of 'Plank road'

From: GCIDE

Plank \Plank\, n. [OE. planke, OF. planque, planche, F. planche, fr. L. planca; cf. Gr. ?, ?, anything flat and broad. Cf. Planch.]
1. A broad piece of sawed timber, differing from a board only in being thicker. See Board. [1913 Webster]
2. Fig.: That which supports or upholds, as a board does a swimmer. [1913 Webster]
His charity is a better plank than the faith of an intolerant and bitter-minded bigot. --Southey. [1913 Webster]
3. One of the separate articles in a declaration of the principles of a party or cause; as, a plank in the national platform. [Cant] [1913 Webster]
Plank road, or Plank way, a road surface formed of planks. [U.S.]
To walk the plank, to walk along a plank laid across the bulwark of a ship, until one overbalances it and falls into the sea; -- a method of disposing of captives practiced by pirates. [1913 Webster]