Definition
In old English law, the share of a deceased man's personal estate to which his wife and children were entitled as of right, independent of any will or bequest. The reasonable part represented a legally protected floor on inheritance — a customary fraction of the estate that the decedent could not freely dispose of and that the surviving family could claim and recover.
The surviving spouse and children each held an entitlement to their respective reasonable parts. The mechanism for enforcing this right was the writ *de rationabili parte bonorum* — a common law writ directed at the executor or administrator to compel delivery of the rightful shares.
Common Confusion
REASONABLE PART should not be confused with DOWER or CURTESY, which were distinct common law entitlements tied to real property rather than personal estate. Reasonable part operated exclusively in the realm of goods and chattels. Nor should it be conflated with FORCED SHARE or ELECTIVE SHARE — the modern statutory descendants that serve a similar protective function in American law but arise from entirely different procedural and legislative frameworks.
Why It Matters in Research
This term is almost entirely historical. It belongs to the medieval and early modern English common law of succession and will rarely appear in American cases or statutes as operative law. Researchers encounter it in three contexts:
First, in tracing the lineage of modern forced-share statutes. American jurisdictions progressively replaced the customary reasonable part doctrine (along with dower and curtesy) with statutory elective share regimes. Understanding what reasonable part protected — and why courts and legislatures found it inadequate — contextualizes the development of the Uniform Probate Code's elective share provisions.
Second, in reading early English treatises and reports. Blackstone's Commentaries (2 Bl. Com. 492) discusses the doctrine directly, and researchers working in colonial-era American law or early republic estates cases may encounter citations to it. Burrill's reference to Blackstone is the most useful anchor.
Third, in writ practice. The writ *de rationabili parte bonorum* appears in Fitzherbert's *Natura Brevium* (F. N. B. 122), cited by both Rapalje & Lawrence and Bouvier. Researchers encountering this writ in historical pleading records should understand it as the procedural vehicle for the reasonable part claim, not an independent substantive right.
The term carries no active doctrinal weight in modern American law. It does not appear in the U.S. Code or in any modern Uniform Act under this name. Treat it as a historical marker rather than a live research thread unless the research question is explicitly genealogical or comparative.
Historical Dictionary Support
The four source dictionaries converge cleanly on the substance: reasonable part is the share of personal estate to which the wife and children of a deceased man were entitled at common law. There is no meaningful divergence among them.
Burrill adds the most analytical texture, noting the Blackstone citation (2 Bl. Com. 492) and distinguishing reasonable part from abstractions like "reasonable time" — a reminder that not all "reasonable" compounds carry the same doctrinal character.
Rapalje & Lawrence provide the most procedurally useful entry, identifying the writ *de rationabili parte bonorum* and anchoring it to Fitzherbert's *Natura Brevium* at page 122. Their entry also clusters the term with neighboring concepts — "reasonable portions," "reasonable rate," "reasonable reward" — suggesting the dictionary was designed for practitioners encountering these phrases in instruments and statutes rather than purely for academic reference. That cluster is not legally related; it is merely alphabetical.
Bouvier essentially tracks Rapalje & Lawrence verbatim on this point, which is consistent with Bouvier's general practice of synthesizing from authoritative secondary sources.
What none of the historical dictionaries address is how the reasonable part doctrine was displaced. The silence is telling: by the time these dictionaries were compiled (mid-to-late 19th century), the doctrine was largely obsolete in American practice, having been superseded by statutory dower rights and, eventually, elective share statutes. Researchers should not expect the dictionaries to trace that transition.
Jurisdictional Note
Reasonable part as a common law doctrine was never uniformly adopted across American states. Some colonies and early states recognized it; others did not. By the mid-19th century it had been substantially replaced everywhere by statutory provisions. It retains significance primarily as English legal history and as background doctrine for understanding American succession law reform.