Definition
A cause of action is the legal basis upon which a party brings a lawsuit — the combination of facts and legal theory that entitles a plaintiff to seek a remedy from a court. More precisely, it is the existence of those facts and circumstances that, recognized by law, give one person a right to pursue a judicial remedy against another. Without a valid cause of action, a claim cannot survive and a court has no basis to grant relief.
A cause of action has two inseparable components: (1) a legal right held by the plaintiff, and (2) a violation of that right by the defendant. The facts must not merely describe a grievance but must map onto a recognized legal theory — negligence, breach of contract, fraud, trespass, and so forth. A wrong without a remedy, or a remedy sought without a cognizable wrong, is not a cause of action in the legal sense.
The term is used in two closely related but distinct senses:
1. Substantive: The underlying right itself — the entitlement that the law protects and that has been infringed.
2. Procedural: The pleaded claim in a complaint — the formal vehicle through which the plaintiff asserts that right before the court.
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Common Language
Modern common usage (Wiktionary): "Cause of action" is not a term in general civilian vocabulary. Where it appears in ordinary speech, it is borrowed directly from legal usage and carries the same general meaning: a reason or basis to sue someone.
Historical common usage (Webster's 1913): Webster's 1913 does not carry a dedicated entry for "cause of action" as a compound term. "Cause" is defined broadly as "that which produces an effect; the antecedent of a consequence." "Action" in the legal sense is noted as "a suit or process, by which a demand is made of a right in a court of justice."
The gap matters. In ordinary language, "cause" suggests a grievance or motivation — a reason to be upset. In law, "cause of action" is far more demanding: it requires not just a harm but a legally cognizable harm tied to a recognized theory. Many genuine grievances, even serious ones, do not constitute causes of action because the law does not recognize a duty, right, or remedy in those circumstances.
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Common Confusion
CAUSE OF ACTION vs. CLAIM: In federal practice, Rule 8 of the Federal Rules of Civil Procedure shifted pleading language from "cause of action" to "claim for relief," and many modern courts use these terms interchangeably. They are not identical. A single cause of action (say, negligence) may give rise to multiple claims, and a single complaint may assert multiple causes of action. Researchers working across eras will encounter both terms in overlapping and sometimes inconsistent ways.
CAUSE OF ACTION vs. CAUSE (in causation): The word "cause" appears throughout tort and criminal law in a distinct sense — factual and proximate causation. A researcher encountering "cause" in a negligence or criminal context should not conflate that doctrine with cause of action. The encyclopedia entries on proximate cause and criminal causation address that separate body of law.
CAUSE OF ACTION vs. RIGHT OF ACTION: These are related but not interchangeable. A cause of action refers to the facts giving rise to a legal claim. A right of action refers to the procedural capacity to bring that claim to court — which may be defeated by limitations periods, standing problems, or assignment rules, even when the underlying cause of action exists.
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Core Elements
For a cause of action to be legally cognizable, the following elements are generally required:
1. Legal right: The plaintiff must hold a right recognized by law — a property interest, contractual entitlement, personal right, or statutory protection.
2. Corresponding duty: The defendant must owe a duty, obligation, or legal restraint with respect to that right.
3. Breach or violation: The defendant must have acted or failed to act in a way that violated the duty.
4. Damage or injury: The plaintiff must have suffered a recognized harm as a result — though some causes of action (such as trespass or nominal damages claims) do not require proof of actual damages.
5. Causal connection: The breach must be causally linked to the harm, to the degree required by the applicable legal theory.
The specific elements vary by cause of action type. Negligence requires duty, breach, causation, and damages. Breach of contract requires a valid contract, breach, and damages. Each legal theory carries its own required showing.
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Why It Matters in Research
The phrase "cause of action" is one of the most frequently encountered terms in American and English legal writing across every era, but its meaning has shifted enough to create genuine traps for researchers.
In older common law pleading — especially before the Field Code reforms of the mid-nineteenth century and later the Federal Rules of Civil Procedure — the cause of action was tightly bound to the form of action. A plaintiff did not simply assert a cause of action for negligence; he brought an action on the case, or trespass, or assumpsit. The factual cause of action had to be mapped onto a recognized writ. Researchers reading pre-code cases should understand that the procedural vehicle and the substantive right were intertwined in ways that modern law has since separated.
The Field Code (New York, 1848) and its successors in other states expressly abolished the forms of action and replaced them with a single civil action in which a plaintiff would plead a "cause of action." This was a deliberate terminological and conceptual shift. When Rapalje & Lawrence were writing in 1883, this transition was underway but uneven across jurisdictions.
Federal researchers must track the further shift to "claim for relief" under the 1938 Federal Rules, which loosened pleading standards and moved away from "cause of action" language. Post-Twombly and Iqbal (2007, 2009), federal courts scrutinize whether a complaint plausibly states a claim — which is functionally equivalent to asking whether a cause of action is adequately alleged, but the analytical framework is different from earlier pleading doctrine.
State courts vary. Many state systems retained "cause of action" terminology well into the twentieth century. Researchers working in state court records, especially pre-1940, should expect to see the term used in the older, more formalistic sense.
Statutes of limitations research requires careful attention: limitations periods run from the accrual of a cause of action, and when a cause of action "accrues" is itself a contested legal question that varies by jurisdiction and claim type.
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Historical Dictionary Support
Rapalje & Lawrence define "cause of action" as "the right to bring an action; the fact or combination of facts which gives rise to a right of action." The entry draws the distinction between the cause of action (the underlying facts and right) and the right of action (the procedural capacity to sue), a distinction the authors treat as meaningful and which modern courts have sometimes collapsed.
Rapalje & Lawrence's treatment reflects the late nineteenth-century transitional moment: the forms of action had been abolished in code pleading states, but courts were still working out what "cause of action" meant when freed from its procedural housing. The definition they provide is primarily substantive — focused on the facts and right, not the procedural vehicle — which aligns with the direction courts and commentators were moving.
What Rapalje & Lawrence do not fully address is the question of accrual — when a cause of action comes into existence for limitations purposes — which would become one of the most litigated questions surrounding the term in the twentieth century. Researchers should not expect historical dictionaries of this era to anticipate that doctrinal development.
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Jurisdictional Note
Federal courts use "claim for relief" under the Federal Rules, though "cause of action" remains common in federal case law as a substantive concept. State courts vary considerably: some have retained "cause of action" as the operative pleading term; others follow federal-style rules. Louisiana's civil law tradition gives the underlying concepts a distinct procedural character. Researchers crossing jurisdictional lines should not assume that the term carries identical procedural weight in every forum.
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Encyclopedia Cross-Reference
Torts & Personal Injury Encyclopedia — Negligence: Proximate Cause (Legal Cause and Foreseeability): Essential for understanding the causation element within negligence causes of action.
Criminal Law Encyclopedia — Causation (Actual Cause and Proximate Cause): Addresses causation doctrine in the distinct criminal law context; not to be conflated with cause of action as a civil pleading concept.
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