Glossary
Military Earthworks Terms

Ramp - an incline leading up to the banquette or allowing access to a gun platform. 

Rampart - a broad embankment of earth that supported the functioning elements of a permanent or semi-permanent fortification.  The parapet and banquette were built at the front of the rampart; ramps moved troops from the interior of the work onto the terreplein of the rampart.  In early forts, a rampart was often improvised by constructing double parallel revetments of logs and filling the intervening space with stones and hard-packed earth.  Ramparts typically were not a component of field fortifications but appeared occasionally in simpler form in some artillery works.  Sometimes called a bulwark.

Rapid Entrenchments - fieldworks constructed in the presence of the enemy, usually with a rear or interior ditch and often with ad hoc materials for fill and revetment, also called hasty or temporary entrenchments.  Although built "hastily, " these were rarely built "carelessly," as the modern use of the word might imply.  Experienced soldiers could throw up a shelter trench sufficient to absorb small arms fire in less than an hour with only rudimentary tools.

Ravelin - a detached earthwork open to the rear with two long faces forming a salient angle and two short flanks.  See Detached Works.

Rear - interior, away from the enemy.

Rear-ditch or Interior Ditch - ditch in which soldiers stood to fire over the parapet; most commonly used in rapid infantry entrenchments.  Rear-ditch was the fastest way to entrench because each shovel of earth lowered the ditch and at the same time raised the parapet.  See Ditch.

Redan (Fr.) - a detached fortification with two faces forming a salient angle, often built as an outer work to cover an advanced position.  The work was open at the rear.  A redan was a common form of all military eras.  When bisected by a traverse down its center (along the capital line), it was called a flêche, or "arrow."  When connected to adjacent strong points by curtain walls, it served as a caponière.

Redan Line - a series of redans connected by curtains.

Redoubt - an enclosed fortification designed to be defended from all sides.  The trace of a redoubt could be square, polygonal, or occasionally circular.  A redoubt could stand alone as a detached work, serve as a place of refuge within a larger fortification, or be incorporated into a continuous line of entrenchments as an artillery or infantry strong point.  Redoubts were a common feature of all military eras.

Reentering Angle or Reentrant - angle in an earthwork or line of earthworks that points toward the rear and away from the enemy.  Systems of earthworks were purposely designed with both reentering and salient angles.

Reface - to "turn" or change the facing of an earthwork.

Relief - distance from the crest of the parapet to the bottom of the ditch; relief is a component of the profile.

Regular Approaches - siege operations conducted by building saps, parallels, and breaching batteries, based largely on a system devised for the French armies by Sebastien le Prestre de Vauban (1633-1707). 

Regular and Irregular Works - enclosed earthworks.  Regular works were based on classic models-square or six-sided redoubts, and bastioned forts-and generally appeared balanced in proportion and symmetrical in trace.  Irregular works were adapted to the peculiarities of the terrain and took a variety of shapes and traces.  Although less "elegant" in terms of geometry, irregular works were often measurably stronger than the more rigid, classical prototypes.

Remblai - See Spoil.

Retrenchment - a secondary line of earthworks built to seal off a gap in the main line or to prevent a breakthrough.

Reversed Fire - incoming fire that strikes the rear of a parapet or line of battle. Incoming fire could be direct, enfilading, oblique, plunging, reversed, and ricochet.

Revetment - retaining wall constructed to support the interior slope of a parapet.  Made of logs, wood planks, fence rails, fascines, gabions, hurdles, sods, or stones, the revetment provided additional protection from enemy fire, and, most importantly, kept the interior slope nearly vertical.  Stone revetments commonly survive.  A few log revetments have been preserved due to high resin pine or cypress and porous sandy soils.  After an entrenchment was abandoned, many log or rail revetments were scavenged for other uses, causing the interior slope to slump more quickly.  An interior slope will appear more vertical if the parapet eroded with the revetment still in place.

Ricochet Fire - fire that strikes the ground first then bounds into the air, used primarily by artillery firing a round, solid shot.  The glacis was shaped to deflect ricochet rounds up and over the parapet rather than into it.

Rifle Pits - generically, any grouping of light, rapid entrenchments, usually discontinuous, with a rear-ditch and low parapet.  See Holes and Pits.

Rifle Trench - a parapet for infantry, typically thrown up rapidly with a rear-ditch.  Also called a shelter trench.

Salient - a portion of a system of earthworks that protruded or bulged outward toward the enemy.

Salient Angle - an angle in a work or line of earthworks that pointed toward the enemy.  See Reentering Angle.  Systems of earthworks were designed purposely with both reentering and salient angles.

Sally Port - opening left in the parapet as an entrance to an enclosed earthwork.  All enclosed earthworks had a sally port; called a postern when vaulted or roofed to form a tunnel.

Sandbags - used to strengthen prepared entrenchments and siegeworks, often filled off-site and transported to the work under construction.  A stratum of sand overlying a different base soil, particularly in an artillery work, might indicate the use of sandbags.

Sap - a trench built to connect one parallel to the next in order to advance siegeworks, sometimes built as a zigzag approach or straight with internal traverses.  See Regular Approaches.

Sap Roller - a large wickerwork cylinder rolled ahead of a crew to absorb incoming fire as it worked on a sap.

Sapper - a pioneer or engineer engaged in digging field or siegeworks.

Scarp, Escarp, or Escarpment - inner slope of the ditch, as opposed to counterscarp, the outer slope of a ditch. Both scarp and counterscarp are below grade and are visible components of all ditches.

Sector Without Fire - area in front of a salient angle into which the defenders cannot fire. A sector without fire was extremely vulnerable unless defended by fire directed from another part of the fortification.

Shelter Trench - a simple rifle trench for infantry, typically with a rear-ditch.

Siege Operations - systematic entrenching to approach an enemy's defenses, using classic engineering techniques.  See Regular Approaches.

Siegeworks - earthworks built to advance or retard siege operations.

Skirmish Line - soldiers deployed at intervals in front of the main line of battle to harass the enemy and delay any enemy advance; a row of individual foxholes entrenched by the skirmishers.  Skirmish lines were advanced anywhere from 50-300 yards in front of the main lines, depending on the terrain and proximity of the enemy.  Sharpshooters often manned the skirmish line.

Skirmish Pits or Picket Holes - See Holes and Pits.

Slashing - cutting down all trees in front of a line to create a clear field of fire.  Trees were felled in the same direction with branches toward the enemy, serving as an obstacle to attack.  Downed trees might then be trimmed and arranged more formally into an abattis.

Slit Trench - slang for a short trench, similar to a rifle pit, constructed for 3-5 men.  Often found in a picket line interspersed with foxholes or as shelter in the rear of a main line.

Spoil - earth removed from an excavation, termed in French the déblai.  The spoil provided the bulk of the remblai, that is, the material used to construct a rampart or parapet.

Star Fort - an enclosed work with alternating salient and reentering angles.  A star fort might have from four to eight salient angles projecting toward the enemy.  This was a popular form until the middle of the Civil War, but many engineers considered it to require more work than needed for a strong defense.  Examples of star forts survive from various time periods.

Stockade - generically, a log fort; when used as an adjunct to earthworks, a vertical wall of logs tied or nailed together to protect the flank or gorge of a battery, lunette, or redoubt.  Loopholes were cut in the logs to allow for rifle fire.  The exterior of the stockade wall might be ditched with the earth thrown up against the logs.  Archeological excavation might reveal evidence of the postholes or remains of the post in the ground.

Strong Point - a dominating position, usually high ground, defended by entrenched artillery or a concentration of infantrymen; an artillery work within a continuous line of entrenchments.

Superior Slope - crest of the parapet on which soldiers rested their weapons to fire.  The interior slope was nearly vertical so that a man could stand comfortably against it.  The superior slope inclined slightly toward the enemy.  The exterior slope, which intercepted most incoming fire, inclined more abruptly.  See Parapet.

Supply Cache - a rectangular excavation, usually 5-10 feet on a side and three feet deep, found in rear of the Main Line of Defense.  See Earthworks Complex.  These served as temporary storage for boxes of food or ammunition and are found in sheltered terrain adjacent to a road or a covered way.  On rare occasions in the field or during siege operations, a supply cached might be roofed or partially roofed with logs and earth.

Swallow's Tail - a detached earthwork consisting of two faces joined in a reentrant and two long flanks extending toward the rear and inclining toward the open gorge.

Tenaille (Fr.) Line - a series of adjacent redans, of equal or differing sizes, joined at the flanks with no connecting curtains.

Terreplein (Fr.) - ground level, grade; generically a level area inside an enclosed fortification; in permanent fortifications, the flat surface of the rampart behind the parapet.

Tête-de-pont (Fr.) - an entrenched bridgehead with both flanks anchored on a river, designed to hold a river crossing.

Throw Up Works - to entrench.  Earthworks were described as being "thrown up."

Trace - outline of a fortification as drawn on a plan or "traced" upon the ground.  In terms of engineering, the trace of an earthwork was its most important characteristic.  To be effective, the trace should take advantage of the military strengths of the terrain and mitigate its weaknesses; its design should accomplish its purpose in the overall plan of defense; its length should be adjusted to the number of soldiers designated to hold the position.

Traverse - a short segment of parapet used to prevent incoming enfilade fire from sweeping the length of a line, to protect the rear wall of an enclosed work from a plunging fire from the front, to cover a sally port, or to provide extra protection for a magazine or supply cache.  Traverses were sometimes built of or reinforced by gabions and were usually constructed perpendicular to incoming fire, rather than perpendicular to the defensive parapet.  In rapid entrenchments, traverses might be constructed entirely of logs.

Trench - usually short for entrenchment, sometimes referring to the ditch of an entrenchment or to an auxiliary entrenchment in rear of a rampart.

Trous de loup (Fr.) - rows of pitfalls, 4-6 feet deep, dug in checkerboard fashion in front of an earthwork to obstruct to an attacking force.  Each cone-shaped pitfall concealed a sharpened stake. 

Turned Works - an entrenchment captured by the enemy and refaced, resulting in ditching on both sides of the parapet.

Work - any discrete component of a system of fortifications, applied most often to detached defenses, to forts, or artillery strong points.

Zigzag Trench - See Boyau.

Zone of Contention - No Man's Land, the area separating the deployed skirmishers of the combatants, often defined by the foxholes of the opposing skirmish lines.  Because skirmishers tended to advance or withdraw according to nuances of the terrain and localized pressure, the width of this zone fluctuated.  See Earthworks Complex.

Zone of Fire or Kill Zone - area between the Main Line of Defense and the advanced skirmish or picket line, typically no wider than the effective ranges of standard infantry weapons. In this zone, soldiers cut down trees to clear a field of fire and often erected obstacles, such as an abattis or entanglements, to slow down and break up an attack.  Nothing would remain from such obstructions unless it was the shallow ditch that anchored the abattis.  One might find larger dugouts that held reserve pickets that could be fed out to the skirmish line as needed.  See Earthworks Complex.

Zone of Occupation - area behind the Main Line of Defense.  This zone might extend 200 yards or more behind the front, depending on the terrain.   In this zone were activities of logistics and support, which sometimes left evidence in the form of support trenches, dug-out supply caches, bunkers for officers and non-combatants, or covered ways through which troops and supplies could move unseen from the rear to the front line.  In some cases, artillery positions were constructed to fire over the front lines at distant targets. See Earthworks Complex.

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