A

Antifederalists

Political faction that opposed ratification of the Constitution without a Bill of Rights. Their concerns about federal power over state militias and individual arms rights influenced the Second Amendment's adoption.

See: Anti-Federalist Papers

Arms

Weapons of offense or defense. In the Second Amendment context, includes firearms and other bearable weapons. The Supreme Court has interpreted this to include weapons "in common use" for lawful purposes.

18th Century Usage: Included muskets, rifles, pistols, swords, and other personal weapons.
Modern Application: Includes handguns, rifles, and possibly other weapons in common civilian use.

See: DC v. Heller (2008)

Assault Weapon

Legislative term (not technical) for certain semi-automatic firearms with specific features. Definitions vary by jurisdiction. Constitutional status disputed after Bruen.

See: Assault Weapons Definitions

B

Bear Arms

To carry weapons, particularly for confrontation or defense. The Supreme Court has interpreted this as encompassing both carrying for self-defense and militia service.

Heller (2008): "At the time of the founding, as now, to 'bear' meant to 'carry.'"

See: Keep and Bear Arms

Bill of Rights

The first ten amendments to the United States Constitution, ratified December 15, 1791. Includes the Second Amendment as a protection against federal infringement of the right to keep and bear arms.

See: Bill of Rights Text

Black Codes

Post-Civil War Southern laws restricting freedmen's rights, including prohibitions on firearm possession. These codes prompted federal civil rights legislation and influenced the Fourteenth Amendment.

See: Black Codes & Arms

Bruen Test

The "text, history, and tradition" test established in NYSRPA v. Bruen (2022). Requires government to prove firearm regulations are consistent with the Nation's historical tradition.

See: NYSRPA v. Bruen

C

Collective Right

Pre-Heller theory that the Second Amendment protected only states' rights to maintain militias, not individual rights. Rejected by the Supreme Court in 2008.

See: Collective Right Theory

Common Use

Doctrine that the Second Amendment protects weapons "in common use at the time" for lawful purposes. Protects typical weapons owned by law-abiding citizens for lawful purposes.

Examples: Handguns (most common self-defense weapon), standard rifles
Excludes: "Dangerous and unusual weapons"

See: Common Use Doctrine

Concealed Carry

Practice of carrying a concealed firearm on one's person. Historically more regulated than open carry. Constitutional with objective licensing after Bruen.

Constitutional Carry

State law allowing carrying firearms without a permit or license. Also called "permitless carry."

D

Dangerous and Unusual Weapons

Category of weapons that may fall outside Second Amendment protection. Exact definition remains contested, but includes weapons not typically possessed by law-abiding citizens for lawful purposes.

See: Dangerous and Unusual Weapons

Due Process Clause

Fourteenth Amendment provision through which the Second Amendment was incorporated against the states in McDonald v. Chicago (2010).

See: McDonald v. Chicago

F

Federalist Papers

Series of 85 essays by Hamilton, Madison, and Jay advocating Constitution ratification (1787-88). Numbers 29 and 46 discuss militia and armed citizenry.

See: Federalist Papers

Firearm

A weapon that expels projectiles by the action of explosive powder. Includes handguns, rifles, and shotguns. Modern legal definition in 18 U.S.C. § 921.

Founding Era

Period around the Constitution's framing and ratification (roughly 1787-1791). Courts examine this period's practices to understand original meaning.

Freedmen's Bureau Act

1866 federal law protecting freed slaves' rights, including "the constitutional right to bear arms." Important evidence for understanding Fourteenth Amendment's intent.

See: Freedmen's Bureau Act

H

Heller Decision

District of Columbia v. Heller (2008). Landmark Supreme Court case establishing that the Second Amendment protects an individual right unconnected to militia service.

See: DC v. Heller

Historical Tradition Test

Requirement from Bruen that modern firearm regulations must be consistent with the Nation's historical tradition of firearm regulation.

I

Incorporation

Legal doctrine by which Bill of Rights provisions apply to state and local governments through the Fourteenth Amendment. Second Amendment incorporated in McDonald (2010).

See: Incorporation Doctrine

Individual Right

Interpretation that the Second Amendment protects a personal right of individuals, not just collective state interests. Established in Heller (2008).

See: Individual Right Doctrine

Infringed

To encroach upon or violate. "Shall not be infringed" is the Second Amendment's prohibition on government interference with the right to keep and bear arms.

K

Keep Arms

To have, possess, or own weapons. The Supreme Court has interpreted this as encompassing possession in the home and elsewhere.

See: Keep and Bear Arms

M

May-Issue

Discretionary licensing system where officials could deny carry permits even if objective criteria were met. Ruled unconstitutional in Bruen (2022).

Required: "Proper cause" or "good cause" beyond general self-defense
States affected: New York, California, Hawaii, Maryland, Massachusetts, New Jersey

McDonald Decision

McDonald v. City of Chicago (2010). Supreme Court case incorporating the Second Amendment against states through the Fourteenth Amendment.

See: McDonald v. Chicago

Militia

(mi-LISH-uh)

Historically, all able-bodied male citizens of military age. Today divided into organized militia (National Guard) and unorganized militia (other citizens).

Founding Era: "The whole people" (George Mason)
Current Law: 10 U.S.C. § 246 defines as males 17-45 plus National Guard

See: The Militia

Miller Test

Standard from United States v. Miller (1939) examining whether a weapon has "reasonable relationship to the preservation or efficiency of a well regulated militia."

See: United States v. Miller

N

National Firearms Act (NFA)

1934 federal law imposing taxes and registration requirements on short-barreled rifles/shotguns, machine guns, and suppressors. Upheld in Miller (1939).

Natural Right

Pre-existing right not created by government. Some view self-defense and arms bearing as natural rights recognized, not granted, by the Constitution.

See: Natural Rights Theory

O

Open Carry

Practice of carrying a firearm visibly. Historically less regulated than concealed carry. Constitutional status varies by jurisdiction.

Operative Clause

The second part of the Second Amendment: "the right of the people to keep and bear Arms, shall not be infringed." Contains the actual right being protected.

See: DC v. Heller

Original Meaning

Interpretive method seeking to understand constitutional text as it would have been understood when adopted (1791 for Second Amendment).

P

People, The

In the Second Amendment, refers to individual persons, not a collective body. Consistent with usage in First and Fourth Amendments.

See: The People

Prefatory Clause

The first part of the Second Amendment: "A well regulated Militia, being necessary to the security of a free State." Announces purpose but doesn't limit operative clause.

Privileges or Immunities Clause

Fourteenth Amendment provision. Justice Thomas argues this, not Due Process, should incorporate the Second Amendment.

Prohibited Persons

Categories of people legally barred from possessing firearms: felons, mentally ill, drug users, domestic violence subjects, etc.

See: Prohibited Persons Categories

Proper Cause

New York's former requirement for concealed carry permits: showing special need beyond general self-defense. Struck down in Bruen (2022).

R

Rahimi Decision

United States v. Rahimi (2024). Supreme Court case upholding prohibition on firearm possession by those under domestic violence restraining orders.

Reconstruction Era

Period after Civil War (1865-1877). Important for Second Amendment because Fourteenth Amendment (1868) was intended to protect freedmen's arms rights.

Regulated

In "well regulated militia," means properly functioning or disciplined, not government-controlled. 18th-century usage different from modern meaning.

See: Well Regulated Militia

S

Scrutiny Levels

Traditional tiers of constitutional review (rational basis, intermediate, strict). Rejected for Second Amendment by Bruen in favor of text, history, and tradition test.

See: Levels of Constitutional Scrutiny

Second Amendment

"A well regulated Militia, being necessary to the security of a free State, the right of the people to keep and bear Arms, shall not be infringed." Ratified December 15, 1791.

See: Second Amendment Text

Self-Defense

Core lawful purpose protected by the Second Amendment. Heller called it "the central component" of the right.

Sensitive Places

Locations where firearms can be prohibited consistent with the Second Amendment. Includes schools, government buildings, courthouses. Exact scope disputed.

See: Sensitive Places Doctrine

Shall-Issue

Licensing system where permits must be issued if objective criteria are met. Constitutional under Bruen. Used in 43 states.

Standing Army

Professional military force. Founding-era Americans feared standing armies as tools of oppression, preferring citizen militias.

See: Standing Army Concerns

T

Text, History, and Tradition Test

Constitutional test from Bruen (2022). Government must prove modern firearm regulations are consistent with Nation's historical tradition.

See: Text, History, and Tradition Test

Time, Place, and Manner

Limited restrictions on when, where, and how arms can be carried. Analogous to First Amendment doctrine.

Tyranny

Oppressive government power. Preventing tyranny was a primary purpose of the Second Amendment according to Founding-era sources.

U

Unorganized Militia

Under 10 U.S.C. § 246, all able-bodied males aged 17-45 who are citizens or intending citizens, not in National Guard or Naval Militia.

W

Well Regulated

In 18th-century usage: properly functioning, trained, disciplined. Like a "well-regulated" clock that keeps good time. Not "heavily regulated by government."

See: Well Regulated Militia

Using This Glossary

This glossary provides quick reference for terms used throughout the site. For deeper analysis of key concepts, visit our Key Concepts section. Terms are defined based on current Supreme Court precedent and historical sources.

Note: Legal definitions can vary by jurisdiction and change over time. This glossary reflects general usage in Second Amendment jurisprudence. For specific legal questions, consult qualified counsel.