Definition
Latin. Arms; weapons, whether offensive or defensive; armor. In its broadest classical legal sense, arma encompasses all instruments capable of being used to strike or injure another person. The term appears in Latin legal maxims, medieval English law, and civil law texts, and carries several subordinate compound usages that appear in historical legal materials.
Recognized compound forms found in historical sources:
Arma dare: To dub or make a knight; the formal conferral of arms as part of the ceremony of knighthood.
Arma moluta: Sharp weapons that cut, as distinguished from blunt weapons that break or bruise. The distinction carried significance in older criminal pleading, particularly in describing the nature of an injury.
Arma reversata: Reversed arms; a recognized form of punishment for a traitor or felon, consisting of the symbolic inversion or degradation of heraldic arms.
Common Language
Modern common usage (Wiktionary): In modern general usage, the most prominent meaning of "arma" as an initialism is ARMA — autoregressive moving average, a statistical modeling concept used in time series analysis. In Romance languages, arma and its plural armas remain in common use to mean weapons or arms in the military sense.
Historical common usage: The Latin arma carried its military and heraldic meaning directly into medieval English legal vocabulary without significant transformation, owing to Latin's role as the working language of English law for centuries.
Editorial note: The statistical initialism has no connection to the legal term. Researchers encountering "arma" in historical legal sources should read it exclusively as the Latin term for weapons or arms, not as any modern acronym. The heraldic use — arms or cognizances of families — represents a distinct strand of meaning that diverged from the weapons sense in practice.
Recognized Forms
/SUBTYPES
Arma dare — knighting ceremony; conferral of arms.
Arma moluta — sharp, cutting weapons; a distinction relevant to pleading the nature of wounds.
Arma reversata — reversed or degraded arms as criminal or attainder-related punishment.
Why It Matters in Research
Arma appears most often in Law Mind corpus materials in three distinct contexts: Latin maxims, medieval criminal and tort pleading, and heraldic law. The researcher's first task is to determine which strand is in play.
In Latin maxims, arma typically appears in phrases governing the relationship between law and force — the maxim arma in armatos sumere jura sinunt ("the laws permit the taking up of arms against the armed") being the most common example. These maxims appear in treatises on self-defense, war powers, and necessity. The maxim silent leges inter arma, referenced by Anderson, belongs to the same family and appears in materials on martial law and emergency powers.
In pleading contexts, arma moluta versus blunt weapons mattered because old criminal indictments and civil actions for assault or battery sometimes specified the character of the weapon. A researcher reading Fleta or early English criminal records will encounter this distinction and must understand it as a technical descriptor, not mere description.
The heraldic use — arma as the arms or cognizances of families — connects arma to a body of law entirely distinct from criminal or tort law: the law of armory, the jurisdiction of the College of Arms, and disputes over the right to bear particular coats of arms. Do not assume a reference to arma in a legal context involving families or estates is about weapons; it may be about heraldic identity.
Compound forms (arma dare, arma reversata) appear in sources treating feudal tenure, treason, and attainder. Arma reversata as a punishment for treason connects to the broader attainder complex — researchers following that thread should move to the related materials on forfeiture, corruption of blood, and heraldic degradation.
Historical Dictionary Support
All four source dictionaries agree on the core meaning: Latin for arms, weapons offensive and defensive. Burrill adds the most substantive civil law gloss, noting that arma in the civil law extended beyond swords, shields, and helmets to include clubs, stones, and all things encompassed within tela (weapons or missiles). The citation to Co. Litt. 161b, 162a (Coke on Littleton) is the principal common-law authority Burrill points to.
Black's Second Edition is the most comprehensive of the shelf sources on compound forms, providing arma dare, arma moluta (citing Fleta lib. 1, c. 33, par. 6), and arma reversata (citing Cowell's Interpreter). Anderson's entry is the most economical, directing the researcher outward to Arms, Lex (for the silent leges maxim), and Vis (for the vi et armis complex).
The shelf sources collectively understate the heraldic dimension. The definition line "arms or cognizances of families" appears in both Black's editions but receives no development. A researcher working in heraldic or armorial jurisdiction will need to go beyond these dictionary entries.
Jurisdictional Note
Arma as a live operative legal term is largely confined to historical English and civil law materials. It does not appear as a term of art in modern United States, English, or Commonwealth statutory law. Researchers will encounter it almost exclusively in Latin maxims, medieval pleading records, and treatise literature.
Encyclopedia Cross-Reference
See Law Mind Encyclopedia: Arms and Armory; Attainder and Corruption of Blood; Latin Maxims in Anglo-American Law.