Pronunciation: (bool'wurk, -wôrk, bul'-), [key]
1. a wall of earth or other material built for defense; rampart.
2. any protection against external danger, injury, or annoyance: The new dam was a bulwark against future floods.
3. any person or thing giving strong support or encouragement in time of need, danger, or doubt: Religion was his bulwark.
4. Usually, bulwarks. Naut.a solid wall enclosing the perimeter of a weather or main deck for the protection of persons or objects on deck.
to fortify or protect with a bulwark; secure by or as if by a fortification.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.