Definition
Convention carries distinct meanings across several legal contexts. The common thread is agreement or assembly — a coming together of persons or of wills — but the legal weight of the term shifts dramatically depending on the domain.
1. CONTRACT AND CIVIL LAW: A convention is a mutual agreement or engagement between two or more parties. In Roman law, convention (conventio) referred to the informal underlying agreement that supplied the subjective element of a contract — the meeting of minds — but did not by itself create a legally enforceable obligation until clothed in a required formality such as stipulatio. This Roman distinction between the bare agreement and the actionable contract carried significant influence into civil law systems and informs how civilian-tradition jurisdictions approach contract formation. In general civil law usage, convention is a broad term encompassing contracts, pacts, treaties, and agreements of all kinds.
2. INTERNATIONAL LAW: A convention is a formal multilateral agreement between sovereign states, functionally equivalent to a treaty. Conventions typically address areas of international concern — commerce, human rights, private international law, or diplomatic relations — and are often concluded under the auspices of international organizations. Well-known examples include the Hague Conventions on private international law and the United Nations Convention on the Rights of the Child. In domestic legal research, conventions become relevant when incorporated into national law by statute or when courts apply them to interpret domestic obligations.
3. CONSTITUTIONAL AND POLITICAL LAW: A convention is a formal deliberative assembly of delegates convened for a specific governmental purpose. In American constitutional law, the most significant usage is the Article V convention — an assembly of state delegates that may be called to propose amendments to the Constitution. Constitutional conventions also describes the assemblies that drafted or amended state and federal constitutions. In English constitutional history, a convention parliament was an extraordinary assembly of the Houses of Lords and Commons convened without the sovereign's summons, justified only by necessity — the Parliament that restored Charles II being the canonical example.
4. POLITICAL PARTY AND NOMINATING CONVENTIONS: In American political practice, a convention refers to the formal assembly of party delegates that nominates candidates for office and adopts party platforms. This usage is primarily procedural and political rather than strictly legal, but it intersects with election law and party regulation.
5. CUSTOMARY PRACTICE: In legal and constitutional usage, convention also describes an established practice or informal rule that governs conduct without formal legal enforcement — constitutional conventions in this sense being understood norms that constrain governmental actors even absent a positive legal sanction.
Common Language
Modern common usage (Wiktionary): A meeting or gathering; a formal deliberative assembly of mandated delegates; a formal agreement, contract, rule, or pact; a treaty or supplement to such; a practice or procedure widely observed in a group, especially to facilitate social interaction; a custom.
Historical common usage (Webster's 1913): The act of coming together; a meeting or assembly of persons, especially of delegates or representatives; general agreement or concurrence; arbitrary custom or usage.
The common-language definitions capture the term's range well — both assembly and agreement — but give no indication that in Roman and civil law the term had a precise technical meaning distinguishing an unenforceable mutual engagement from a legally operative contract, nor that in constitutional law the term carries significant structural consequences for sovereign authority and amendment procedures.
Recognized Forms
/SUBTYPES
CONVENTIO (Roman law): The informal agreement underlying a contract, distinguished from the binding obligation created by supervening formality.
CONVENTION PARLIAMENT (English constitutional history): An assembly of Lords and Commons without royal summons, valid only by necessity and subsequent ratification.
CONSTITUTIONAL CONVENTION: A delegate assembly convened to draft or amend a constitution; under Article V of the U.S. Constitution, a mechanism for proposing amendments upon application of two-thirds of state legislatures.
INTERNATIONAL CONVENTION: A multilateral treaty, typically codifying rules of general application among signatory states.
PARTY NOMINATING CONVENTION: A political assembly of delegates for candidate selection; governed by election law and party rules rather than contract or constitutional doctrine.
CONVENTIONAL (adjective): Agreed upon by the parties; arising from agreement rather than by operation of law. A conventional lien or estate is one created by express agreement, as opposed to one arising by law. See Anderson's Dictionary of Law.
Why It Matters in Research
Convention is one of the most contextually variable terms in the Law Mind corpus, and researchers must anchor every instance to its domain before assigning meaning. A citation to a "convention" in a nineteenth-century contracts treatise is almost certainly invoking the Roman civil law sense of informal agreement. The same word in a diplomatic correspondence or international law text refers to a multilateral treaty. In constitutional materials, it means a delegate assembly — and the stakes of that meaning are considerable when researching Article V amendment procedures or founding-era constitutional debates.
The Roman law distinction between convention and contract is a persistent research trap. Historical sources in the civil law tradition — and American treatises drawing on that tradition — use convention to mean the meeting of minds that is necessary but not sufficient for an enforceable contract. Researchers working in early American contract law or equity, or in Louisiana and other mixed-jurisdiction sources, should not assume that a "convention" is an enforceable obligation without examining the surrounding formality analysis.
In international law research, the Hague Convention materials in the corpus require attention to domestic implementing legislation: a convention's legal force in any given jurisdiction depends on whether and how it was ratified and incorporated. The Hague Convention on Intercountry Adoption, for example, operates through the Intercountry Adoption Act in the United States and should be researched in tandem with that statute.
For constitutional research, the Article V convention provisions have generated substantial scholarly debate and comparatively sparse judicial interpretation. Researchers should treat historical sources carefully: the convention parliament materials in English constitutional history are analogically useful but not directly applicable to American Article V analysis.
The adjective conventional — meaning arising from agreement rather than operation of law — appears throughout property, mortgage, and family law sources. Its appearance in historical texts signals a distinction between consensual arrangements and those imposed by legal construction.
Historical Dictionary Support
The historical sources converge on two primary clusters of meaning — agreement and assembly — but differ in which they foreground and how precisely they define the agreement sense.
Bouvier's Law Dictionary provides the most expansive civil law treatment, defining convention as a general term comprehending "all kinds of contracts, treaties, pacts, or agreements" and specifically as the consent of two or more persons to form, dissolve, or modify an engagement. Bouvier cites Domat and the Digest, grounding the definition firmly in the civilian tradition. This is the most useful historical source for civil law contract research.
Black's Law Dictionary (both editions) offers the most technically precise Roman law account, distinguishing convention as the subjective element — mutual engagement — from the objective formality required to create legal obligation. This precision is absent in Bouvier's broader formulation and makes Black's the preferred source for analyzing the Roman law architecture of contract formation.
Burrill's Law Dictionary and Rapalje & Lawrence focus almost exclusively on the English constitutional meaning — the convention parliament — and treat the agreement sense only in passing. Burrill's citation to Blackstone's Commentaries is the appropriate starting point for English constitutional history research on this point.
Anderson's Dictionary of Law is notable for explicitly flagging the adjectival form conventional and distinguishing conventional from legal as categories of legal creation — by agreement versus by operation of law. Anderson also notes postal conventions between nations and constitutional conventions by delegates, usefully bridging the international and constitutional senses. No historical source provides more than passing treatment of the nominating convention, which is a later American political development lying largely outside the classical dictionary tradition.
Jurisdictional Note
The civil law meaning of convention as a general term for agreement remains operative in Louisiana and in Québec-influenced legal contexts, and in comparative law analysis of French, Spanish, and Latin American civil codes. Common law jurisdictions use contract as the primary term and treat convention primarily in its international and constitutional senses. International convention carries different domestic legal weight in monist jurisdictions (where ratified treaties automatically become domestic law) than in dualist jurisdictions like the United States (where congressional implementation is required).
Encyclopedia Cross-Reference
The Amendment Process — Article V, Conventions, and Ratification (The Law Mind Constitutional Law Encyclopedia)
Adoption — International / Intercountry Adoption (Hague Convention, IAA) (The Law Mind Family Law Encyclopedia)
Conventional Mortgages — Qualification, Underwriting, and Private Mortgage Insurance (The Law Mind Real Estate Transactions & Construction Encyclopedia)