Definition
Perquisitio (Latin) is the civil and common law term for acquisition of property by purchase — that is, by one's own voluntary act or agreement — as distinguished from acquisition by descent or inheritance. Where property passes to an heir through operation of law upon the death of an ancestor, it comes by descent. Where it is obtained by any other means — by conveyance, gift, devise, or contract — it is perquisitio. The term is the Latin root from which the English legal concept of "purchase" in its broad technical sense derives.
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Common Language
Modern common usage (Wiktionary): Purchase means to obtain something by paying money for it; a commercial transaction exchanging money for goods or property.
Historical common usage (Webster's 1913): Purchase — the act of buying; the acquisition of anything by rendering an equivalent in money.
The gap here is significant. In ordinary English, "purchase" means buying with money. In its legal and Latin technical sense — perquisitio — the term encompasses any voluntary acquisition that is not inheritance, including gifts, devise by will, and exchange, with no requirement that money change hands. A researcher encountering perquisitio in a historical source should not read it as a cash sale; it signals a broader category that contrasts specifically with descent.
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Common Confusion
Perquisitio is closely associated with, and often confused with, the English term "purchase" as used in its technical legal sense. The confusion runs in two directions. First, modern readers assume "purchase" means a money transaction; the Latin perquisitio and the technical legal "purchase" both mean something far broader. Second, perquisitio should not be confused with perquisite (a privilege or incidental benefit attached to an office), despite superficial similarity in spelling and a shared Latin root. The two words occupy entirely different doctrinal territory.
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Why It Matters in Research
Researchers working in early common law sources, feudal property texts, or treatises drawing on Roman and civil law will encounter perquisitio as the operative term for voluntary acquisition. The word appears most frequently in discussions contrasting the two root modes of property acquisition — purchase and descent — a distinction that carried enormous practical weight in feudal tenure, inheritance rules, and the law of real property.
Several traps await the unwary. First, the breadth of the term: in historical sources, a devise by will, a gift inter vivos, and a bargained sale are all perquisitio. Any argument that turns on how the property was acquired must account for this wide net. Second, the term anchors a foundational conceptual pair — perquisitio versus hereditas (or descent) — that structures much of classical common law property analysis. Seeing one term in a source means the other is operating implicitly as the contrast. Third, because the term largely disappeared from English legal usage as Latin was displaced, later digests and abridgments may translate it simply as "purchase" without flagging the breadth of the original meaning. Researchers relying on translated or summarized sources risk importing the narrow modern meaning into a context where the broader technical sense was intended.
The term also surfaces in civil law and mixed civil-common law jurisdictions, where the purchase/descent distinction carries its own procedural and substantive consequences.
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Historical Dictionary Support
Both Black's Law Dictionary and its Second Edition define perquisitio identically: "Purchase. Acquisition by one's own act or agreement, and not by descent." The entries are brief but precise. The emphasis on the negative definition — not by descent — reflects the genuine doctrinal function of the term, which existed primarily to mark out a category in opposition to hereditary succession.
Neither edition elaborates on the full scope of voluntary acquisitions covered, nor do they distinguish between the civil law roots of the term and its absorption into common law usage. For a fuller treatment of the purchase/descent dichotomy as it operated in English common law, researchers should consult Blackstone's Commentaries, Book II, which develops the distinction at length without using the Latin term perquisitio but relies entirely on the conceptual framework it represents.
The brevity of the historical dictionary entries is appropriate given the term's function as a root term that anchors a much larger doctrinal structure treated elsewhere.
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Jurisdictional Note
The purchase/descent distinction encoded in perquisitio applies across common law jurisdictions, though the consequences of the distinction (for intestacy, for feudal incidents, for the application of particular statutes) varied considerably by jurisdiction and era. Civil law systems employ the same conceptual pair, though under different structural frameworks. Researchers working in Louisiana, Quebec, or other mixed jurisdictions should confirm which tradition controls the specific question at hand.
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