1. Protection from hostile observation and fire provided by an obstacle such as a hill, ridge, or bank. 2. A vertical distance by which a position is concealed from enemy observation. 3. To shield from enemy fire or observation by using natural or artificial obstacles.

the arrangement of defensive fortifications to protect against enemy fire

a depression or other shallow land feature that prevents direct fire from a prepared position, like a ditch or culvert

To raise, as a rampart, so as to shelter interior works commanded from some higher point.

Maneuvering to obtain cover from terrain