Also known as: rule of construction · rules of statutory construction · rules of contractual construction · canons of construction · interpretive canons
Written by attorneys · grounded in primary & secondary sources — see below
Guidelines or presumptions that courts apply to resolve ambiguities in the language of legal instruments when the parties' intent is not clearly expressed. These aids attribute a likely intention to the parties based on common assumptions and can be rebutted by evidence of a contrary intention.
Rajesh Rao executed a deed conveying land in State X to a buyer and included a clause designating the law of State Y to govern interpretation. When a dispute arose over whether the deed created a fee simple or a life estate, the court applied State Y's rules of construction to the ambiguous language. The designation controlled the outcome even though the land lay in State X.
Ralph Richardson's trust instrument left property to his heirs at law after a life estate. When the trustee sought instructions, the court refused to apply the doctrine of worthier title to create a reversion in Richardson. The statute abolished the doctrine as both a rule of law and a rule of construction, so the language did not presumptively create a reversionary interest.
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Ricardo Rojas conveyed an interest in land located in State Z by an instrument that contained no choice-of-law clause. A later dispute required construction of an ambiguous reservation clause. The court applied the rules of construction that the courts of State Z would use because no other state had been designated.
Renee Rogers contracted with Rocky Mountain Mining to supply equipment under an agreement silent on delivery tolerances. Evidence showed that the parties and the industry had long treated a two-percent variance as acceptable. The court used that course of performance and trade usage as a rule of construction to resolve the ambiguity in favor of the established practice.
Radiance Media invented a genetically engineered bacterium and sought a patent under the statute covering any new and useful manufacture or composition of matter. The examiner argued the living organism fell outside the statutory language. The court applied rules of construction that give expansive meaning to broad statutory terms unless Congress clearly intended otherwise.
Redwood Bank held mortgages on homes whose owners faced foreclosure during a severe economic crisis. A state statute extended redemption periods and imposed a moratorium. The bank challenged the law under the Contracts Clause. The court used rules of construction that read the constitutional prohibition in light of the emergency circumstances and the state's police power.
Rules of construction apply when the language of a governing instrument is ambiguous and no direct evidence resolves the meaning. They supply a presumed intention based on common assumptions and yield to any contrary intention shown by competent evidence.
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The core function remains the same across instruments, but specific rules are tailored to the context. Wills and trusts often use rules addressing lapse, class gifts, and per stirpes distribution, while contracts emphasize course of performance and trade usage.
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Yes. Most rules of construction are rebuttable presumptions. A party may introduce extrinsic evidence showing that the donor or parties intended a different result, and that evidence controls if it meets the applicable burden of proof.
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When an instrument designates a particular state's law for construction, that state's rules of construction govern. Absent a designation, the rules applied by the courts of the situs control.
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…the legislature has not expressed." United States v. Dubilier Condenser Corp. , 289 U. S. 178, 199 (1933). Guided by these canons of construction, this Court has read the term "manufacture" in § 101 in accordance with its dictionary definition to mean "the production of articles for use from raw or prepared materials by giving to…