Civil War Glossary – Basic Military Terminology

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When you are reading a history book or article, do you find some of the terms confusing? If so, this Civil War Glossary can help.

Last Update: February 14, 2022 (9:42 pm)


A military organization that is organized into corps that are grouped into divisions that consist of brigades.^


Large-caliber, mounted guns. Also called ordnance or cannon. One of three branches of an army, the artillery manages the operation of large-caliber weapons.^


An organization of four to eight companies, usually artillery. A battalion is generally smaller than a typical regiment, which is fully staffed at ten companies. At Gettysburg, Confederate artillery battalions rolled-up under divisions. (Union artillery was organized into brigades.) ^


An artillery unit that consists of four to six cannon and the gunners who operate and maintain them. Batteries belong to brigades. ^

Border State

A slave state whose government did not secede from the Union. Slaves in border states were exempt from Lincoln’s Emancipation Proclamation (which freed slaves), because those state governments were not at war with the Union.  The border states were Delaware, Kentucky, Maryland, Missouri, and West Virginia (until June 1863).^


During the Civil War, trenches made of natural material (earth, rocks, and wood) that protect soldiers as they fire at an attacking force. For example, at the Battle of Chickamauga, Union Maj. Gen. George H. Thomas’s 14th Corps built breastworks on a slight ridge on the east side of Kelly Farm. ^


The back end of a weapon’s barrel. The opposite of its muzzle.^


A brigade consisted of about 4,000 Civil War soldiers who are grouped into regiments. A general commands a brigade.^


In the Civil War, a two-wheeled carriage pulled by horses that carries ammunition for an army.^


The diameter of a bullet.^


A weapon that is mounted on wheels. Sometimes, cannon are called “guns.” They are maintained and operated by army artillery units.^


A firearm whose barrel is longer than a revolver and shorter than a rifle or musket. Breech-loading carbines were commonly used by cavalry for use of use on horseback.^


Killed, wounded, missing (or captured).^


A military unit that provided reconnaissance and screening support (while on horseback) to a Civil War army.^


A regimental flag that color bearers carry into battle for the purpose of keeping a unit together during the chaos of battle. Also, a symbol of regimental pride; the loss of colors was considered a disgrace (and the capture of an enemy flag was an honor).^


A general term for an officer who leads a military unit.^


The smallest military unit of a Civil War army, a company consisted of no more than 100 soldiers (at the time of the unit’s formation). Companies are usually led by captains and grouped into regiments.^


Having to do with states who had seceded from the United States of America, or sympathizers to that cause. The Confederacy is also called The South or the Confederate States of America (CSA).^


The largest military unit of a Civil War army, a corps consisted of tens of thousands of soldiers that are grouped into divisions (that are grouped into brigades of regiments). Due to differences between USA and CSA military structures, as well as battlefield losses over time, the size of each corps varied widely up to a maximum theoretical size of 36,000 soldiers.^


Confederate States of America, under President Jefferson Davis. The government formed in opposition to the United States of America when southern states seceded from the Union.^


Civil War army corps consist of divisions of about 12,000 soldiers, but this number could be far less due to battle casualties. Divisions consist of regiments that are formed from companies. A general commands a division.^

Eastern Theater

For military operations during the U.S. Civil War, the area of land that includes Virginia, Pennsylvania, Maryland, and east coast. For example, the battles of Manassas (Bull Run), Fredericksburg, Gettysburg, and Antietam (Sharpsburg) were fought in the eastern theater.^


A weak military formation in which a battle line can be attacked on its end and turned.^


Referring to the government, laws, or armies of the United States of America. During the United States Civil War, Federal troops represented the North in the conflict between North and South. Often used as a synonym for the Union (of the United States), as opposed to the Confederate States of America).^


The left or right end of a military battle line. On battlefield monuments, the abbreviations “L.F.” and “R.F.” mark the left and right flanks of regiments.^


An artilleryman who operates a cannon (or “gun”).^


One of three branches of a Civil War army, along with cavalry and artillery. The infantry is comprised of foot soldiers who carry small arms.^

Medal of Honor

First awarded in 1863, the highest military decoration granted by the United States government to American military service personnel for distinguished acts of valor.^

Minié ball

A grooved, .58 caliber lead bullet invented by Frenchman Claude-Étienne Minié and the most common ammunition for Civil War rifles.^

Mortal Wound

A wound that ultimately leads to death.^


Smoothbore (non-rifled) shoulder arms that are loaded from the barrel’s front end with gunpowder and lead balls. Although muskets were replaced by rifles in the Civil War, weapons manufacturers would sometimes identify rifles as a type of musket.^


The front end of a weapon’s barrel. The opposite of its breech.^

Order of Battle

A detailed listing of the military units and their commanders that participated in a particular battle.^


When formed, a military unit of about 100 companies, for a total of 1,000 soldiers. The regiment is the most monumented military unit on U.S. Civil War battlefields. Regiments are grouped into brigades (that are grouped into divisions within corps). Generally, a colonel commands a regiment.^


A pistol that has a revolving chamber in which to load bullets. In the Civil War, revolvers were side arms for officers, cavalry, and sometimes artillery.^


A long-barreled, grooved firearm that was widely used in the Civil War and which was replacing older smoothbore technology.^


An angled military formation whose left and right sides are exposed to potential flanking attacks.^


A soldier belonging to a specially-trained infantry unit that carried precision shoulder arms.^


A firearm whose barrel has a smooth interior (and is not grooved like a rifle).^

Spencer Repeating Rifle

Invented in 1860, a .52-caliber breech-loading small arm that could fire seven shots in thirty seconds. At the Battle of Chickamauga, Union Col. John T. Wilder’s Brigade used this weapon effectively at Alexander’s Bridge.^


Having to do with states who remained loyal to the United States of America (USA), or sympathizers to that cause. The Union is also called The North or Federals.^


United States of America, under President Abraham Lincoln during the U.S. Civil War. The government that fought a civil war against the Confederate States of America.^

Western Theater

For military operations during the U.S. Civil War, the area of land that is south of Virginia and east of the Mississippi River. For example, the battles of Shiloh, Vicksburg, and Chickamauga were fought in the western theater.^

Wing Commander

A military general with operational responsibility for more than one infantry corps.^

More on the Web …

The American Battlefield Trust’s Glossary of Civil War Terms.