bulwark

n 1 wall, esp of earth, built as a defence 壁垒（尤指用泥土堆砌者）; 防御工事. 2 (fig 比喻) person or thing that supports, defends or protects 支持, 防御或保护的人或事物: Democracy is a bulwark of freedom. 民主是自由的保障. 3 (usu pl 通常作复数) ship's side above the level of the deck 舷墙（甲板线以上的船侧）.

bulldozer, bullet, bullet-headed, bullet-proof, bulletin, bulletin board, bullfight, bullfighter, bullfighting, bullfinch, bullfrog, bullhorn, bullion, bullish, bullock, bullring, bullshit, bully, bully-boy, bulrush, bum, bumble, bumble-bee, bumbling, bumf (also bumph), bump, bumper, bumper-to-bumper, bumph, bumpily, bumpiness, bumpkin, bumptious, bumptiously, bumptiousness, bumpy, bun, bun-fight, bunch, bundle,