bastion
noun [ C ] uk/ˈbæs.ti.ən/ us/ˈbæs.ti.ən/
堡垒
something that keeps or defends a belief or a way of life that is disappearing or threatened
British public schools are regarded as one of the last bastions of upper-class privilege. 英国公学被视为上流阶级特权的最后堡垒之一。
棱堡（城堡和堡垒的突出部分）
a part of the wall of a castle that sticks out from it in order to protect it