Entrenchment (fortification)

An entrenchment, in military terminology, refers to a type of field fortification consisting of a ditch or trench, with the excavated earth used to build a parapet, breastwork, or other protective embankment along the forward edge. The primary purpose of an entrenchment is to provide defenders with cover from enemy fire while allowing them to fire upon attacking forces. Entrenchments can range from simple, hastily constructed ditches to elaborate systems of interconnected trenches, fortified with obstacles and strongpoints.

The effectiveness of an entrenchment depends on factors such as its depth, width, and the height of the parapet. Deeper trenches provide better protection from projectiles, while wider trenches make it more difficult for attackers to cross. The parapet serves as a shield against direct fire, and can also be used to mount weapons or observation posts.

Entrenchments are typically constructed in defensive positions to slow down or break up enemy attacks, providing time for reinforcements to arrive or for the defenders to launch a counterattack. They have been used throughout military history, from ancient sieges to modern warfare, and are particularly effective in situations where one side has a numerical or technological disadvantage. Variations include communication trenches (narrow trenches connecting larger systems) and fire trenches (positions along the front line). The degree of sophistication and permanence can vary considerably.