Definition
A number that is uncertain or indeterminate in quantity — one that may be increased or diminished at will rather than fixed at a specific figure. The term appears principally in two legal contexts:
1. Corporate and associational law: A corporation or unincorporated association is said to have an indefinite number of members when its governing instruments place no ceiling on membership. Where membership is indefinite, the default rule — absent contrary provision in a charter or bylaws — is that a majority of those actually present at a duly convened meeting constitutes a sufficient quorum or acting body.
2. Contractual and statutory interpretation: A term, class, or quantity described by an indefinite number lacks the specificity needed to fix a legal obligation without further definition. Courts and drafters treat indefinite numbers as potentially unenforceable or as requiring extrinsic evidence to give them content.
Common Language
Modern common usage (Wiktionary): "Indefinite" means not clearly defined, not fixed, or of uncertain duration or extent. An "indefinite number" in ordinary speech simply means an unspecified or unknown quantity.
Historical common usage (Webster's 1913): "Indefinite" is defined as not definite; not limited, defined, or specified; not precise or certain; vague; as, an indefinite time.
The gap here is subtle but matters in legal research: in ordinary usage, "indefinite" mainly signals vagueness or imprecision. In law, the term carries an additional, affirmative implication — that the number is capable of expansion or contraction by design, not merely unknown. A membership body with an indefinite number is not simply one whose membership is uncounted; it is one whose governing structure deliberately leaves the count open-ended. That structural quality, rather than mere vagueness, drives the legal consequences.
Common Confusion
INDEFINITE NUMBER vs. UNCERTAIN NUMBER: These phrases are sometimes used interchangeably in older sources, but the distinction matters. An uncertain number is simply one not yet determined. An indefinite number implies a structural feature — the number is by its nature variable and may be adjusted at will. The corporate-law consequences (majority-of-those-present rule, quorum calculations) attach to the indefinite category, not merely to any situation where a headcount is unavailable.
INDEFINITE NUMBER vs. INDEFINITE PAYMENT: Black's Law Dictionary places the entry for "indefinite payment" immediately after "indefinite number," and researchers working through historical dictionaries sometimes conflate the two. Indefinite payment is a distinct Scots law concept — payment made by a debtor to a creditor without specifying which of several debts it should satisfy. The two terms share the modifier but address entirely different legal problems.
Why It Matters in Research
For corporate law research, the indefinite-number rule is a default gap-filler: when a charter or bylaw is silent on quorum or voting thresholds, courts historically reached for this concept to supply a workable standard. Researchers examining early American corporate charters — particularly nineteenth-century charters for membership organizations, religious societies, and voluntary associations — should check whether the instrument specifies a fixed membership. If it does not, case law interpreting the charter may have applied the indefinite-number default without naming it explicitly.
For contract research, "indefinite number" connects directly to the enforceability problem addressed in the Contracts — Indefiniteness and Agreement to Agree encyclopedia entry. Where a contract defines a class or quantity by reference to a number that can be altered at will by one party, courts may treat the obligation as illusory or unenforceable for lack of mutuality. This is a live trap in supply agreements, output contracts, and requirements contracts with variable quantity terms.
The maxim "indefinitum æquipollet universali" — the indefinite is equivalent to the universal — appears in Black's entry and in older equity and statutory construction opinions. Researchers encountering that maxim in historical sources should understand it as a canon of interpretation, not a rule of thumb with modern binding force. It expressed the idea that an unqualified term reaches everything in its class. Its application was contested even in the nineteenth century and should not be imported into modern analysis without checking whether a court or jurisdiction explicitly adopted it.
Jurisdictional variation in corporate law means the default quorum rule for indefinite-number bodies has been codified differently across states. Modern nonprofit corporation statutes and model act provisions have largely displaced the common-law default, so the historical rule is most relevant when interpreting instruments predating those statutes.
Historical Dictionary Support
Black's and Bouvier's agree on the core definition — a number capable of increase or diminution at pleasure — and Bouvier's adds the corporate-law application with useful specificity: majority of those present governs absent charter or bylaw provision. Black's usefully appends the indefinitum maxim, which gives the concept a grounding in broader interpretive doctrine.
Neither source develops the contract-law dimension with any depth, which reflects their era. The enforceability problem posed by indefinite quantities in bilateral contracts was worked out primarily through twentieth-century case law and the Uniform Commercial Code. Researchers should treat the historical dictionary entries as authoritative for the corporate-membership context but as incomplete guides for commercial contract analysis.
Jurisdictional Note
Modern corporate statutes — particularly the Model Nonprofit Corporation Act and its state adoptions — have codified quorum and voting rules that displace the common-law indefinite-number default. In states following the Revised Model Nonprofit Corporation Act, researchers should look first to the statute and the entity's governing documents rather than to common-law precedent on indefinite membership.
Encyclopedia Cross-Reference
Contracts — Indefiniteness and Agreement to Agree (The Law Mind Contracts & Commercial Law Encyclopedia)