Webster's Revised Unabridged Dictionary · 1913

Bulwark

Bulwark ({not transcribed}) , noun

[Akin to Dutch bolwerk, German bollwerk, Swedish bolwerk, Danish bolvark, bulvark, rampart; akin to German bohle plank, and werk work, defense. See Bole stem, and Work, n., and compare Boulevard.]

1.
(Fortification) A rampart; a fortification; a bastion or outwork.
2.
That which secures against an enemy, or defends from attack; any means of defense or protection.
The royal navy of England hath ever been its greatest defense,... the floating bulwark of our island. — Blackstone
3.
(Nautical) The sides of a ship above the upper deck, usually a fencelike structure around the deck.

Bulwark ({not transcribed}) , transitive verb

To fortify with, or as with, a rampart or wall; to secure by fortification; to protect.
Of some proud city, bulwarked round and armed With rising towers. — Glover