Military fortification is a term used to describe the construction of defensive structures, such as walls, towers, and trenches, to protect a military base or settlement from attack. The two crossword solutions for this term are HEAD (4 letters) and REDAN (5 letters). A HEAD is a type of fortification that is built in the shape of a triangle, with the point facing towards the enemy. A REDAN is a type of fortification that is built in the shape of a V, with the point facing away from the enemy. Both types of fortifications are designed to provide protection from enemy fire.