Other forms: gangplanks
A gangplank is the board laid from a ship to the shore. Cross the gangplank, raise the gangplank, up the gangplank.
The gang in it is an old word meaning a going or a way, which survives in gangway. It is narrow, springy and usually roped on one side only, which is why crossing a gangplank in a swell is not the trivial thing it looks.
1noungangplankThe board laid from a ship to the shore.
“The passengers walked carefully down the gangplank onto the dock.”
gangplank is a board.
Gang, an old word for a going or passage, plus plank. Gangway is the same first element.
From gang + plank.
Etymology from Wiktionary, CC BY-SA