Definition

Noun
- A bridge-like structure that goes from a vessel to the shore and allows for access.
Origin
Probably earlier than the 17th century. From Anglo-Saxon, gang, meaning path or course. Plank comes from Middle English, planke, meaning board.
Comments
Also known as a gangway. The term is pretty self-explanatory since plank can simply refer to a flat board of wood. Some gangplanks are sturdier and better built than others, so watch your step.
References
Rogers, J.G. (1985). Origins of Sea Terms. Mystic Seaport.