Definition
De placito (Latin: "of a plea") is a formal Latin phrase used in common law pleading to identify the type of action being brought. It appeared in the caption or opening recitation of a declaration — the initial pleading in a common law civil action — to specify the legal nature of the plaintiff's claim. The phrase functions as a descriptor, not a substantive element of the pleading itself.
Common forms include:
1. De placito debiti — of a plea of debt. Used in declarations for actions of debt.
2. De placito conventionis fractae — of a plea of breach of covenant. Used in actions on covenant.
3. De placito transgressionis — of a plea of trespass. Used in trespass actions.
4. De placito transgressionis super casum — of a plea of trespass on the case. Used in case actions, the predecessor to modern negligence and other indirect injury claims.
The phrase was not a term of legal substance but a term of legal form. It told the court and opposing party, at a glance, which of the recognized common law forms of action the plaintiff was invoking.
Common Confusion
De placito is sometimes loosely grouped with Latin terms of substantive legal doctrine — it is not. It belongs to the procedural vocabulary of common law pleading forms, not to doctrine. Researchers encountering it in historical records should not treat it as a term of art carrying independent legal weight. Its significance is diagnostic: it identifies the form of action, which then carries the substantive rules, elements, and pleading requirements that do matter.
Why It Matters in Research
This term is almost exclusively a feature of pre-code common law pleading. Researchers will encounter de placito in English and early American court records, writs, and printed form books, typically before the mid-nineteenth century procedural reforms. In the United States, the Field Code (New York, 1848) and the reforms that followed it abolished the forms of action, eliminating the practical function of this phrase. After code pleading took hold, declarations were replaced by complaints, and formal Latin identifiers like de placito disappeared from practice.
The research value of the phrase is primarily historical and interpretive. When reading an early American declaration or English precedent book, the de placito clause tells you which form of action applied — and the form of action determines everything: available defenses, the theory of liability, what needed to be proved, and what relief was possible. Misreading or overlooking the de placito clause in an old document means potentially misidentifying the entire procedural and substantive context of the case.
Corpus researchers working in early American case reports, English Year Books, or Register of Writs materials will find this phrase routinely. It is common in printed declaration forms and form books from the seventeenth through early nineteenth centuries. Burrill cites the Registrum Brevium (Register of Writs) as a source for the trespass formulation, which signals the phrase's deep roots in English writ practice.
Historical Dictionary Support
Black's (1st ed.), Black's (2nd ed.), and Burrill's are in full agreement on the core definition: de placito means "of a plea" or "of or in an action," and its function was to describe the type of action in formal pleadings and proceedings. There is no substantive disagreement across the three sources.
Burrill provides the most useful treatment by supplying the specific compound forms — de placito debiti, de placito conventionis fractae, de placito transgressionis, and de placito transgressionis super casum — along with the reference to the Registrum Brevium. This specificity is valuable because it grounds the phrase in actual practice and allows researchers to connect the Latin formula to the recognized forms of action. Black's entries, both editions, state the definition competently but offer no examples, leaving the practical meaning underexplained for anyone unfamiliar with common law pleading forms.
None of the three sources address the disappearance of the phrase following procedural reform, which is the most important contextual fact for American researchers. That gap must be filled by reference to the history of code pleading.
Jurisdictional Note
De placito is a term of English common law pleading form. American jurisdictions adopted it during the colonial and early national periods but abandoned it as code pleading spread through the states in the second half of the nineteenth century. Researchers working in Louisiana or other civil law jurisdictions will not encounter it in local practice at any period.