Words: crownwork
Part of speech: n
Definition: a type of fortification, like a hornwork, but consisting of a full bastion with the walls on either side ending in half-bastions from which longer flank walls run back towards the main fortress.
Example: The crownwork was used to extend the fortified area in a particular direction often in order to defend a bridge, prevent the enemy occupying an area of high ground, or simply strengthen the overall fortifications in the expected direction of attack.