A defensive structure.

Walk about Zion, and go round about her: tell the towers thereof. Mark ye well her BULWARKS, consider her palaces; that ye may tell it to the generation following. ( Psalm 48:12-13 )

Source: A King James Dictionary. (Used with permission. Copyright © Philip P. Kapusta)

Bibliography Information

"Entry for 'Bulwark'". A King James Dictionary.