Plank  —n. 1 long flat piece of timber. 2 item in a political or other programme. —v. 1 provide or cover with planks. 2 (usu. Foll. By down) colloq. A put down or deposit roughly or violently. B pay (money) on the spot.  walk the plank hist. Be made to walk blindfold along a plank over the side of a ship to one's death in the sea. [latin planca]