Definition
AB INTESTAT is a Latin-derived civil law phrase meaning "from an intestate" — that is, from a person who died without leaving a valid will. It describes an inheritance or succession that arises because the deceased left no testamentary instrument to govern the distribution of their estate. The phrase functions as a modifier: property passes ab intestat when the law, rather than the decedent's expressed wishes, determines who inherits and in what shares.
The term is closely related to, and often used interchangeably with, the longer Latin form AB INTESTATO, the more formally complete construction found in Roman and civil law sources. Both forms convey the same meaning: succession by operation of law in the absence of a will.
Common Confusion
AB INTESTAT and AB INTESTATO are variants of the same phrase, not distinct legal concepts. Researchers encountering either form in historical sources should treat them as equivalent. The shortened form AB INTESTAT appears more frequently in French-influenced civil law jurisdictions and older Lower Canadian sources; AB INTESTATO predominates in Latin treatises and common law dictionaries drawing on Roman law. Neither form should be confused with INTESTATE used as a standalone noun or adjective, which in modern usage simply describes the decedent or the condition of dying without a will, rather than specifically characterizing the nature of the succession itself.
Why It Matters in Research
The primary research trap with AB INTESTAT is jurisdictional and linguistic. The phrase surfaces most often in sources rooted in the civil law tradition — Quebec, Louisiana, and the continental European legal literature that influenced both. Researchers working in common law archives will rarely encounter it; when they do, it typically signals a document with civil law influence, a treatise drawing on Roman sources, or a conflict-of-laws discussion.
The Bouvier citation to 2 Lower Canada reports (2 Low. Can. 219) is a significant signal: this phrase was active in the legal vocabulary of Lower Canada, where French civil law and English common law coexisted and collided. Researchers examining inheritance disputes, succession conflicts, or property records from that jurisdiction in the early-to-mid nineteenth century should expect the phrase to carry civil law weight, not merely be a Latin flourish on an otherwise common law concept.
Story's Conflict of Laws reference (Story, Confl. L. 480) is equally instructive. AB INTESTAT appears in conflict-of-laws analysis precisely because succession rules varied sharply between civil and common law jurisdictions. When historical courts or treatise writers asked whose law governed an inheritance — the domicile of the decedent, the situs of the property, or some other rule — the phrase often marked the moment the civil law framework was being invoked or distinguished.
Modern legal research databases will rarely index this phrase directly. Researchers should search for it in digitized historical law reports, French-language legal sources, and civil law treatises, and should cross-reference results against INTESTATE SUCCESSION and HEREDITARY SUCCESSION entries to build a complete picture.
Historical Dictionary Support
Bouvier's Law Dictionary treats AB INTESTAT and AB INTESTATO together, defining them as describing "an inheritance derived from an ancestor who died without making a will." Bouvier's synthesis is characteristically economical: it confirms the civil and common law dual usage, grounds the phrase in both a Lower Canadian case reference and Story's conflict treatise, and moves on. What Bouvier does not address — and what researchers should note — is the structural difference between civil law intestate succession regimes (which historically operated through a fixed hierarchy of heirs rooted in Roman law) and common law intestacy (which developed separately through statutes of distribution and descent). The phrase AB INTESTAT carries the civil law pedigree; using it to describe common law intestacy, while technically intelligible, can introduce imprecision in historical analysis.
No other shelf sources in the current Law Mind corpus contain independent entries for this term. Its treatment remains dependent on Bouvier and the civil law tradition he was synthesizing.
Jurisdictional Note
The phrase is native to civil law jurisdictions and appears most frequently in Quebec, Louisiana, and sources drawing on Roman or French law. Common law jurisdictions use INTESTATE and INTESTACY as the standard terminology. Researchers should not assume that legal rules described under this phrase in one jurisdiction map cleanly onto intestacy rules in another.