The bastion represents fortified resilience and calculated defense, its projecting design allowing defenders to repel attackers from multiple angles. Poets use the bastion both literally, in depictions of historical sieges and fortresses, and metaphorically, to describe steadfast resistance or protection in broader contexts, such as a bastion of faith or liberty, extending the term's martial origins into symbolic language describing unwavering strength.

A bastion is a projecting fortified structure, part of a larger fortification, designed to defend against assault. Bastions revolutionized military architecture in the sixteenth century, replacing medieval towers with angled, gunpowder-resistant formations that allowed defenders to cover all approaches with crossfire. The classic star fort, with its multiple bastions, became the dominant fortification design for centuries. In poetry and political rhetoric, bastion has become a metaphor for any stronghold or institution that protects values or ideas—a "bastion of freedom" or "bastion of tradition." The term carries connotations of endurance, security, and resolute defense. Related concepts include fortress, citadel, and redoubt. In military history, the fall of a bastion often signals the collapse of an entire defensive system, making it a powerful symbol of vulnerability despite apparent strength.