Definition
De coste is a Law French term meaning "from the side" or "on the side," used in medieval English legal writing to denote collateral relationship — that is, a line of descent or connection that runs alongside the direct line rather than through it. In the context of inheritance and property succession, de coste describes relatives who are not in a direct ascending or descending line from a common ancestor, but who share that ancestor through a branch. A sibling, aunt, uncle, or cousin stands de coste to a given person; a parent or child does not.
The term is not a legal standard or doctrine in itself. It is a descriptive modifier used in older pleading and treatise writing to identify the nature of a relational claim — most often in the context of who may inherit, who may bring a real action, or whose blood relationship to land matters for a given legal purpose.
Common Confusion
De coste is sometimes encountered alongside de linea recta (of the direct line) and de stirpe (of the stock or root). These are not synonyms. De linea recta describes direct lineal descent — parent to child, grandparent to grandchild. De coste describes collateral connection through a shared ancestor. De stirpe refers to representation by the stock, the principle by which a branch of descendants stands in the place of a deceased ancestor. A researcher encountering any of these terms in a medieval or early modern source should treat them as technically distinct, even when they appear near one another in the same passage.
Why It Matters in Research
De coste appears almost exclusively in early English legal sources — treatises and compilations drawing on the Anglo-Norman legal vocabulary of the thirteenth and fourteenth centuries. Britton, the anonymous treatise cited in Burrill, is among the earliest systematic treatments of English common law written in Law French rather than Latin, dating to the late thirteenth century. References to de coste in that context are not casual synonyms for "collateral" — they are technical markers that carry weight in determining who has standing to bring a real action, who falls within the relevant degree of kinship for a given inheritance rule, and how a court should construe a claimant's relationship to land in dispute.
For Law Mind corpus researchers, the key navigational point is this: when de coste appears in a primary source, it is almost always embedded in a question about property succession or the right to bring a possessory or proprietary action. The term itself does not resolve the legal question — it frames the relational posture of the claimant. Researchers working with early land records, inheritance disputes, or writs touching on collateral heirs should treat de coste as a signal to examine the surrounding text carefully for which specific rule of descent or degree of kinship is being invoked.
Modern legal writing does not use this term. It has no counterpart in contemporary statutes or rules. Its relevance is entirely historical — it survives in the research context as vocabulary for reading and translating older sources accurately.
Historical Dictionary Support
Burrill's Law Dictionary provides the only entry among the shelf sources. The definition is spare: "From, or on the side (à latere); collateral," with a citation to Britton, chapter 119. Burrill's gloss is accurate and sufficient for identification purposes, but it does not explain the operative legal contexts in which the term appeared or how it related to the broader structure of medieval inheritance doctrine.
No other shelf source addresses de coste directly. The term is absent from later American legal dictionaries because Law French vocabulary of this kind did not survive the transition to modern common law pleading. Researchers should not expect to find the term in nineteenth- or twentieth-century legal sources except in historical commentary.
The citation to Britton is the most useful anchor. Britton is a recognized primary source of late thirteenth-century English law. Researchers who need to understand the context in which de coste was used operationally should consult Britton directly, keeping in mind that the text is in Law French and requires careful translation.
Jurisdictional Note
De coste has no current jurisdictional application. It is a medieval Law French term with no modern statutory or common law footprint in any American or English jurisdiction. Its relevance is limited to historical legal research, translation of early sources, and the study of medieval English property and succession law.