the.com/bastion

means A stronghold or group that firmly defends and preserves something, especially an idea, value, or way of life.

from From French 'bastion,' from Italian 'bastione,' from 'bastire' meaning to build. The military sense is literal — it named the projecting angular part of a fortification designed to give defenders overlapping lines of fire. The word marched into figurative use by the 1500s-1600s, so that 'bastion of free speech' or 'last bastion of tradition' stands guard the same way the old stone ramparts did, just against different enemies.