Definition of rolling chock in US English:

rolling chock

noun

  • 1A piece of wood fastened to the centre of a yard and secured by a parrel, in order to steady the yard against the rolling movements of the ship.

  • 2A fin-like projection fitted under the bilge or along the hull in order to counteract the hull's tendency to roll.

Origin

Mid 19th century; earliest use found in Arthur Young (fl. 1846).