Definition
A legal or moral obligation binding a person to act or refrain from acting in a particular way. In law, duty is the correlative of right: wherever a recognized right exists in one party, a corresponding duty rests upon another party or upon persons generally to respect or fulfill that right. The term operates across nearly every field of law, and its precise meaning varies by context.
1. Tort law. The threshold requirement that a defendant owe an obligation of care to the plaintiff before liability can attach. Without a cognizable duty, no negligence claim can succeed, regardless of harm caused. The existence and scope of duty is ordinarily a question of law for the court.
2. Contract law. An obligation arising from an agreement, requiring a party to perform, refrain from acting, or exercise a standard of care. Duties in contract may be delegated unless personal in nature or prohibited by the contract's terms.
3. Fiduciary law. A heightened obligation arising from a relationship of trust and confidence — as between a corporate director and shareholders, a trustee and beneficiaries, or an attorney and client. Fiduciary duties typically include the duty of care and the duty of loyalty.
4. Constitutional and public law. An obligation imposed by law on governmental actors, agencies, or public officers to act or refrain from acting in specified ways.
5. Tax and customs law. A tax or tariff levied on imported or exported goods. In this sense the word functions as a near-synonym for tariff or impost.
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Common Language
Modern common usage (Wiktionary): That which one is morally or legally obligated to do; a tax placed on imports or exports; the state of being responsible for a particular task.
Historical common usage (Webster's 1913): That which a person is bound by moral obligation to do or refrain from doing; any assigned service or business; that which is due or owed.
In ordinary English, duty carries a strong moral flavor and is used loosely to describe anything one ought to do, from civic obligations to personal responsibilities. The legal concept is more precise: law distinguishes sharply between a moral duty (which may be real but unenforceable) and a legal duty (which creates actionable rights and obligations). Bouvier's recognized this gap directly, noting that a person may have a duty to be temperate in eating without any enforceable legal obligation to do so. The customs meaning — a tax on goods — is a wholly separate legal usage that shares only the word with the obligation-based meanings.
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Common Confusion
Duty vs. obligation vs. liability. These terms overlap but are not interchangeable. A duty is the antecedent requirement — the obligation to act or forbear. Liability is the consequence of breaching a duty. An obligation is sometimes used as a synonym for duty but more often describes the binding force of a contract or legal requirement generally. Burrill notes that duty is broader in signification than debt: an inchoate duty may exist that has not yet ripened into an enforceable debt.
Duty vs. right. Because duty is the correlative of right, confusion arises when the two are treated as independent concepts. A right without a corresponding duty is legally inert; a duty without a corresponding right holder is typically a matter of public law rather than private obligation.
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Core Elements
In tort law — where the existence of duty is most frequently litigated — courts assess duty by reference to:
Relationship between the parties. Some relationships (employer-employee, doctor-patient, common carrier-passenger) give rise to duty by their nature. Others require analysis.
Foreseeability of harm. Most jurisdictions ask whether the plaintiff was within the foreseeable zone of danger created by the defendant's conduct.
Public policy considerations. Courts weigh whether recognizing a duty in a given category of case would impose unworkable burdens, chill beneficial conduct, or produce results inconsistent with broader legal policy.
Scope of the duty. Even where a duty exists, its scope may be limited. A duty to warn, for instance, may not extend to all possible harms.
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Recognized Forms
/SUBTYPES
Duty of care. The obligation to act with the standard of care a reasonably prudent person would exercise under similar circumstances.
Duty to defend. In insurance law, an insurer's obligation to provide a defense to an insured against covered claims — typically broader than the duty to indemnify and triggered by the allegations in the complaint.
Duty to indemnify. An insurer's obligation to pay a judgment or settlement actually covered by the policy.
Duty of loyalty. A fiduciary's obligation to act in the interest of the beneficiary or principal rather than in self-interest.
Duty of good faith. An obligation — arising in contract, fiduciary relationships, and certain statutory contexts — to deal honestly and without bad faith or concealment.
Non-delegable duty. A duty that cannot be transferred to a third party or contractor; the obligated party remains liable even if performance is delegated.
Absolute duty. A duty owed to the world at large, the breach of which gives rise to liability without regard to the relationship between the parties.
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Why It Matters in Research
Duty is one of the most structurally important terms in the Law Mind corpus and one of the most treacherous to research historically. Several traps warrant attention.
The moral-legal line shifts by era and jurisdiction. Historical sources — particularly Bouvier's — treat moral and legal duty as overlapping but distinct categories without always marking where one ends and the other begins. Nineteenth-century texts frequently invoke duty in a predominantly moral register. Researchers working in older materials should not assume that a recognized "duty" in a historical treatise translates into an enforceable legal obligation by modern standards.
Tort duty doctrine has evolved significantly. The modern foreseeability-and-policy framework for establishing duty in negligence is a twentieth-century development. Earlier materials may reflect a more relationship-bound or categorical approach, where duty arose from recognized relationships (innkeeper, carrier, physician) rather than from general negligence principles. Research bridging eras should account for this structural shift.
The customs usage creates false cross-references. In trade law, tariff, impost, and duty are near-synonyms. In a mixed corpus search, sources discussing "import duties" will surface alongside sources analyzing tortious duty of care. Context disambiguation is essential.
Fiduciary duty terminology has proliferated. The duty of care and duty of loyalty as fiduciary concepts were not always sharply distinguished in early corporate law materials. Modern formulations — particularly post-Delaware case law — have refined these into distinct doctrines. The Law Mind Business Organizations Encyclopedia entries reflect the modern formulation; historical sources may use the terms more loosely.
Corpus connections: Duty of care links to negligence, standard of care, and proximate cause. Fiduciary duty links to trust, agency, and corporate governance. Duty to defend and duty to indemnify are distinct insurance law doctrines that must be researched separately despite their apparent overlap. Non-delegable duty connects to vicarious liability and independent contractor doctrine.
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Historical Dictionary Support
The historical dictionaries converge on the correlative relationship between duty and right, and on the distinction between moral and legal duty, but they diverge meaningfully in emphasis and scope.
Black's (both editions) provides the most jurisprudentially precise formulation: duty is the correlative of right, and wherever a right exists in one person, a corresponding duty rests on another or on persons generally. Black's also acknowledges the wider, extra-jural usage — moral obligations that rest on ethical foundations but have not been translated into enforceable legal requirements. This acknowledgment is valuable precisely because it names the gap rather than collapsing it.
Bouvier's is more expansive and more explicitly moral in its framing, defining duty as a human action conformable to the laws requiring obedience, and distinguishing duty from legal obligation on the ground that duty cannot always be legally enforced. Bouvier's observation that we have a duty to love our neighbors without any corresponding legal obligation is a useful illustration of the moral-legal distinction, though modern tort law has complicated the picture by recognizing limited affirmative duties in some relational contexts.
Burrill's contributes the important note that duty is broader than debt, and that an inchoate duty may exist before it has ripened into an enforceable debt. This distinction matters in contract and property research, where inchoate rights and duties appear frequently in pre-modern materials.
Anderson's entry retrieved for this term is misaligned — the text concerns duress of goods rather than duty — suggesting that historical indexing in that source does not reliably support duty as a standalone entry. Researchers should not rely on Anderson's for this term without direct verification.
What the historical sources largely miss: the modern tort law framework for analyzing whether a duty exists as a threshold legal question, the development of specific fiduciary duty doctrine in corporate law, and the insurance law distinctions between duty to defend and duty to indemnify. These are twentieth-century elaborations that post-date the historical dictionaries entirely.
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Jurisdictional Note
Duty doctrine in tort law varies significantly across U.S. jurisdictions, particularly on the question of whether courts apply a general foreseeability standard, a categorical approach, or a multi-factor balancing test to determine duty. A minority of states reject the foreseeability-of-plaintiff analysis in favor of policy-driven categorical rules. In contract and fiduciary law, Delaware's influential corporate law formulations of the duty of care and duty of loyalty are frequently treated as the default framework in business organization research but should not be assumed to govern in other jurisdictions.
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Encyclopedia Cross-Reference
The Law Mind Contracts & Commercial Law Encyclopedia: Insurance Contracts — Duty to Defend and Duty to Indemnify
The Law Mind Contracts & Commercial Law Encyclopedia: Delegation of Duties — General Principles and Non-Delegable Duties
The Law Mind Business Organizations & Corporate Law Encyclopedia: Board of Directors — Duty of Good Faith and Oversight (Caremark Duties)
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