Definition
All descendants of a person in a direct line, extending to the remotest generation. In legal contexts, posterity denotes the full line of lineal descendants — children, grandchildren, and all those who follow in an unbroken line of descent — rather than collateral relatives such as siblings, cousins, or nieces and nephews.
The term appears in two distinct legal registers:
1. PRIVATE LAW (wills, trusts, deeds, succession): Posterity identifies the class of persons who take under an instrument drafted to benefit a grantor's or testator's descendants indefinitely. Courts have generally read the word to reach all lineal descendants without limit of generation unless the instrument restricts it.
2. PUBLIC LAW (constitutional and organic instruments): Posterity appears in preamble language — most prominently in the Preamble to the U.S. Constitution ("to ourselves and our Posterity") — to express the intergenerational ambition of a foundational document. In this register the word functions less as a technical term of art and more as a statement of constitutional aspiration, though courts and commentators have invoked it when interpreting the intended scope of constitutional protections.
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Common Language
Modern common usage (Wiktionary): All future generations, especially the descendants of a specific person; also, future audiences or future times generally ("recorded for posterity").
Historical common usage (Webster's 1913): The race that proceeds from a progenitor; offspring to the furthest generation; the aggregate of persons descended from an ancestor — contrasted with ancestry. Also used loosely to mean succeeding generations or future times.
The gap between common and legal usage is narrow but consequential. In ordinary speech, posterity often means simply "future people" or "future audiences" in a diffuse, non-genealogical sense ("preserved for posterity"). In law, the word carries a precise genealogical meaning — lineal descent from a specific identified person — and courts have used that precision to resolve disputes about who qualifies as a beneficiary under a will or deed. A researcher who encounters the word in a legal instrument and reads it in the loose common sense risks misidentifying the class of persons intended to take.
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Why It Matters in Research
Posterity is a word that appears rarely in modern drafting — it has been largely displaced by "descendants," "issue," and "lineal heirs" — but it surfaces with some frequency in older wills, deeds, trust instruments, and land grants from the colonial period through the nineteenth century. Researchers working in that corpus face several practical issues.
First, the word's scope in any given instrument may be contested. Courts in some cases read posterity as synonymous with "issue" (which could be construed narrowly as children only) while other courts gave it the full multi-generational reach the dictionaries confirm. The Kentucky decision cited consistently across the historical dictionaries (8 Bush 527) is an anchor for the broader reading.
Second, in constitutional research, posterity in preamble language has been invoked in arguments about standing, intergenerational equity, and the reach of rights to future citizens. It is not a term of art with a binding legal test in this context, but its presence in foundational texts means researchers will encounter it in originalist and structural constitutional arguments.
Third, watch for the distinction between posterity and collateral lines. The historical dictionaries are unanimous that posterity means direct lineal descent only. Instruments that use posterity do not, on that reading, reach nephews, cousins, or other collateral relatives — a distinction that matters in succession disputes where the direct line has failed.
Finally, note that Burrill specifically flags the Louisiana civil law usage, which codified the term's meaning in the Civil Code. Researchers working in Louisiana succession law or in comparative civil law contexts should consult the civil code article directly rather than relying solely on common law dictionary definitions.
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Historical Dictionary Support
The historical sources are in unusually tight agreement. Black's (both editions), Bouvier, Anderson, and Rapalje & Lawrence all converge on the same core formulation: all descendants in a direct line to the remotest generation. The Kentucky citation (8 Bush 527, or 527/525 depending on the source — a minor pagination discrepancy across editions) is the shared authority.
Burrill adds the most texture. He provides the civil law anchor in the Louisiana Civil Code (Art. 3522, num. 26) and frames the word's Latin root (posteritas, from posterus, from post) — useful for researchers tracing the term through civil law and Roman law sources. Burrill's emphasis on "those who come after" keeps the definition simple while acknowledging the civilian tradition that the common law dictionaries do not engage.
Rapalje & Lawrence usefully note the contrast with ancestry, which is the natural doctrinal pairing: posterity looks forward through a line of descent; ancestry looks backward. This opposition occasionally matters in instrument construction when a grant or bequest is worded in terms of both directions.
What the historical sources collectively omit is any treatment of posterity in constitutional or public law usage. That dimension of the word falls outside the private law focus of nineteenth-century legal dictionaries but is essential for modern researchers working in constitutional history or theory.
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Jurisdictional Note
Louisiana treated posterity as a defined civil law term in the Civil Code, giving it codified meaning that common law jurisdictions resolved only through judicial construction. In common law states, the meaning was established case by case, with the Kentucky authority (8 Bush) serving as a widely cited reference point. Researchers working across jurisdictions should not assume that a civil law state's reading of the word transfers directly to a common law instrument, or vice versa.
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Encyclopedia Cross-Reference
Law Mind Encyclopedia — Constitutional Preamble (for the public law register of the term and its interpretive history)
Law Mind Encyclopedia — Succession and Descent (for the private law register, lineal versus collateral distinction, and instrument construction)
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