bastion Definition

bastion
noun

1. A kind of tower which sticks out at an angle from a castle wall.
2. A person, place or thing regarded as a defender of a principle, etc.

Example: He is a bastion of religious freedom
Thesaurus: fortress, citadel, stronghold, bulwark, pillar, redoubt.

Etymology: 16c: French, from Italian bastione, from bastire to build.