Glossary
Military Earthworks Terms

Dam - often used in conjunction with military earthworks to flood an area for defensive purposes.

Déblai - See Spoil.

Dead Angle - See Sector without Fire.

Defilade or Dead Ground - a ravine, gully, or depression within range of an earthwork's weapons that could not be seen or fired into from the defenders' position.

Deliberate Entrenchments - defenses constructed in anticipation of need, to defend a town, depot, or bridge, for example, typically constructed with a front or exterior ditch.  If defending an important position and occupied for a long period of time, deliberate earthworks might be improved to a semi-permanent condition.  Magazines and bombproofs were built.  The parapets might be sodded with grass, revetments faced with sawn planks or stone, roads and ramps paved with flagstones, a well dug, and a more complete drainage system installed.  Frame barracks and storehouses might be constructed within or adjacent to the earthworks for the garrison.

Deliberate Fieldworks - improvements made to an existing line of rapid entrenchments, typically the addition of detached works for artillery.  Also siegeworks.

Demi-bastion (Fr.) - an angular work that projected outward from the corner of an enclosed or detached earthwork.  A demi-bastion consisted of one face and one flank forming a salient angle.  The flank directed fire across the front of an adjacent face or curtain.

Demilune (Fr.) - a crescent shaped parapet protecting a single cannon, typically ditched in front.  Also called an epaulement; in permanent fortifications, a component of the bastion.  The term was often used interchangeably with lunette, but this is imprecise.

Dentate - zigzag or saw-toothed parapet designed to direct fire obliquely left and right across the front, designed to create interlocking fields of fire.  See Cremaillière Line.

Detached Works - fortifications constructed in advance of the main line to delay an enemy's approach or built as components of a line of intervals, generally redans, ravelins, lunettes, or redoubts.  Other variations included swallow's tails, hornworks, crownworks, and priest caps.

Direct Fire - incoming fire striking perpendicular to the parapet or line of battle. Incoming fire could be direct, enfilading, plunging, reversed, and ricochet.

Discontinuous Line - See Line of Intervals.

Ditch - excavation providing soil to construct a parapet.  A ditch could be in front of the parapet (front-ditch or exterior), behind it (back-ditch or interior), or on both sides (double-ditch).  Engineers preferred front-ditch construction whenever time and labor permitted, as it created a stronger profile.  Batteries, redans, lunettes, and redoubts were consistently constructed with a front-ditch.  Back-ditch construction was the fastest way to entrench, and therefore was used most often for rapid infantry entrenchments.  A double-ditch resulted from digging in front to widen an existing back-ditch parapet, from constructing a covered way behind a front-ditched line, or from capture and refacing.  Some evidence of the ditch-a shallow trough-often survives even if its parapet has eroded away.  The scarp and counterscarp are the inner and outer slopes of the ditch.

Double-ditch - parapet with both an interior and exterior ditch.  Double-ditching was used to widen an existing back-ditch parapet or to provide a covered way behind a front-ditch parapet.  An earthwork that was captured and turned (refaced) would have a double ditch.  See Ditch.

Drainage Ditch - See Cunette.

Dugouts and Bunkers - rectangular excavations, usually 5-10 feet on a side, associated with the principal defenses of an earthworks complex.  These typically served a command or logistical function.  On rare occasions in the field or during siege operations, dugouts might be roofed or partially roofed with logs and earth.

Earthworks - any earthen structure excavated for military purposes.  In simplest form, a defensive earthwork was composed of a parapet or mound of earth and a ditch from which the earth was excavated.

Earthworks Complex - consists of the Main Line of Defense, a Zone of Occupation behind the main line, a Zone of Fire in front of it, and a Zone of Contention (No Man's Land) separating advanced positions of the combatants.  The entire fortified front, taking in both combatants, might be a mile ore more deep with each zone identified by a specific grouping of features and artifacts.

Embrasure (Fr.) - a wedge-shaped opening cut to allow artillery to fire through the parapet. A cannon firing en embrasure had a restricted (45-degree) field of fire but the parapet protected the gunners.  The sides, or cheeks, of an embrasure often were reinforced by logs, planks, stones, sandbags, or gabions.  Embrasures were common features of artillery fortifications and often survive as an indentation in the otherwise uniform parapet crest.  Not all indentations are embrasures.  Typically, there is other evidence of the presence of artillery-a gun platform and gun ramp, for example.  A single gun might have had multiple embrasures.  See Barbette.

Enceinte (Fr.) - "body of the place," area of a fort or redoubt enclosed by the parapet.

Enclosed Work - an earthwork designed to be defended from all sides.  See Redoubt.

Enfilade or Enfilading Fire - fire from the flank that swept along the length of a parapet or line of battle.  Enfilading fire could be particularly destructive as incoming rounds might strike multiple targets and no return fire could be brought to bear.  Traverses were often constructed behind a parapet to limit casualties caused by enfilade.  Incoming fire could be direct, enfilading, oblique, plunging, reversed, or ricochet.

Entanglement - obstacles placed in front of an earthwork to trip up and delay attackers, sometimes used to refer to an abattis.  During the Civil War, telegraph wire was strung from stump to stump at shin level to form a "wire entanglement."  Most wire was retrieved or scavenged during or after the war, so little would be expected to survive archeologically.

Entrenchment or Intrenchment - generic term for any form of earthen fortification. In common usage, terms like breastwork, trench, entrenchment (intrenchment), curtain, and fieldworks were applied with little precision.

Epaulement (Fr.) - See Demilune.

Escarp, Escarpment (Fr.), or Scarp - rear or inner slope of a ditch.  In a front-ditch earthwork, a continuation below grade of the exterior slope of the parapet. See Counterscarp.

Exterior Ditch - See Front-ditch.

Exterior Slope - outer side of the parapet that faced the enemy and intercepted incoming fire. The exterior slope typically inclined 45 degrees, the natural angle of repose for most soils.  The interior slope was more vertical to enable defenders to stand directly behind it.  Nearly all extant earthworks in original condition will display some difference in angle between the exterior and interior slopes. See Interior and Superior Slope.

Face - a straight segment of parapet making up a larger earthwork that delivered direct or oblique fire to the front.

Facing - covering or treatment of a slope with sod, sandbags, stone, or other materials.  See Revetment.

Fascine - tightly bound bundle of saplings used to reinforce a parapet or in revetment.  Evidence of the use of fascines might appear as a darker stratum of soil in an excavated cross-section.  See Revetment.

Field of Fire - area within weapons range that can be seen and swept by fire. Fields of fire were often improved by slashing (cutting down) all of the trees or pulling down buildings in front of the line.

Fieldworks - earthworks constructed by armies while actively campaigning, whether on the battlefield or in camp.  Often hasty or rapid entrenchments.

Fill - logs, rails, stones, or other available materials used to add bulk to the parapet; typically gathered and placed along the intended line before digging begins. 

Fire - organized and directed discharge of weapons.

Fire Pits or Mess Holes - See Holes and Pits.

Flank - left or right end of a line of battle or position; side; a segment of parapet thrown back to protect the side of a position or to allow defenders to deliver fire across the front of an adjacent face.

Flanking Fire - fire directed from one segment of parapet to sweep the front of an adjacent segment.

Flêche (Fr.) - a small redan with a central, bisecting traverse giving it the appearance of an arrow.

Fort - an enclosed fortification defended by artillery; a complex, multi-component earthwork; a wooden stockade with corner blockhouses, often with ditching or other earthen components; generically, a military base. 

Fortification - earthen works or other structures erected to defend a place or position.

Fortress - a system of defenses designed to work together as a whole to defend a fixed position. Often a permanent fortification.

Fossé (Fr.) - an exterior ditch fronting a rampart or curtain.

Foxhole - an individual shelter hole.  See Holes and Pits.

Fraise (Fr.) - row of pointed logs set close together and inclined toward the enemy, often erected in the exterior ditch of a redoubt to prevent attackers from scaling the parapets.  Sometimes called a palisade.

Front - exterior, toward the enemy.

Fronting - orientation of an earthwork vis-à-vis the enemy.

Front-ditch or Exterior Ditch - ditch on the outside of a parapet designed as an additional obstacle to assault.  A front-ditch allowed the parapet to have greater bulk and a stronger profile than rear-ditch construction.  This was the engineers' preferred method and was consistently applied to prepared fortifications, to detached works, and artillery fieldworks. It is common to find a mix of front-, rear-, and double-ditch entrenchments in a single continuous line. See Ditch.

Fully Stocked Forest Stand - This refers to a full overstory canopy capable of replenishing the forest floor. Foresters typically use basal area to measure stocking in a forest. A rule of thumb is that the lower limit of full stocking is around 60 square feet of basal area per acre. In pine and pine-hardwood forests, it is 80 square feet per acre. Basal area (BA) = 0. 005454d 2 BA is basal area in square feet and d = tree diameter in inches. Summing the basal area from all trees over an acre provides basal area per acre which is a measure of stocking. Basal area for mature deciduous forests in the eastern United States generally range from 100 to 150 square feet per acre.

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