Fortification

Part of speech: noun (n.)

1. The act of fortifying; the art or science of fortifying places in order to defend them against an enemy.

2. That which fortifies; especially, a work or works erected to defend a place against attack; a fortified place; a fortress; a fort; a castle. Fortification agate, Scotch pebble.

Synonyms: Fortress; citadel; bulwark. See Fortress.