Definition
A Latin maxim meaning "in ambiguous expressions" or "in ambiguous discourses." The phrase introduces a canon of legal construction governing how courts and interpreters should resolve unclear or equivocal language in legal instruments, statutes, contracts, and other documents. Standing alone, the phrase is a header to the full maxim, which directs that ambiguous language should be construed against the party who used it or, in some formulations, in favor of the interpretation least burdensome to the obligor. The complete principle is most commonly rendered: *In ambiguis orationibus maxime sententia spectanda est eius qui eas protulisset* — in ambiguous expressions, the intention of the person who used them is chiefly to be regarded.
The maxim operates as a rule of last resort in interpretation: when the plain meaning of words is genuinely uncertain and other tools of construction have failed to resolve the ambiguity, courts look to the intent of the drafter, or apply the contra proferentem principle to resolve doubt against the party who introduced the unclear language.
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Common Confusion
IN AMBIGUIS ORATIONIBUS is frequently invoked in close proximity to, and sometimes confused with, two related but distinct principles. First, *ambiguitas latens* versus *ambiguitas patens* — the distinction between a hidden ambiguity (one that appears only when the instrument is applied to external facts) and a patent ambiguity (one apparent on the face of the document). The maxim applies most directly to patent ambiguity, where the text itself is equivocal. Second, researchers sometimes conflate this maxim with the *contra proferentem* rule, which specifically places the burden of unclear drafting on the party who drafted the instrument. The *in ambiguis* maxim is broader: it directs attention to the speaker's or drafter's intent as the primary remedy for ambiguity, whereas *contra proferentem* is one specific application of that broader principle, weighted toward protecting the non-drafting party.
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Why It Matters in Research
This phrase appears most often in older equity and common law sources as a citation anchor — a fragment that signals a broader discussion of interpretive canons nearby. Researchers encountering the phrase in historical case reports or treatises should treat it as a pointer, not a standalone rule. Burrill's entry cross-references the fuller discussion under "Ambiguus," which is where the substantive doctrine lives in that dictionary.
The maxim has practical relevance in at least three research contexts. In contract law research, it sits at the foundation of *contra proferentem* and ambiguity doctrine — tracing the phrase in historical sources helps map how modern ambiguity rules developed from Roman and civil law roots through equity into common law. In statutory construction research, the phrase appears in older treatises discussing legislative intent, particularly when statutory language was unclear on its face. In ecclesiastical and civil law contexts, the maxim retained force longer than in common law courts, and researchers working in those jurisdictions or periods will encounter it more frequently.
A navigational trap: because Burrill provides only the phrase and a cross-reference rather than a developed entry, researchers relying solely on Burrill will miss the substantive treatment. The fuller Latin maxim and its applications are discussed in Broom's *Legal Maxims* and Broome's collected canons — both of which Burrill implicitly signals by citing "Broom's Max." under the companion entry. Researchers should follow that thread.
Historical sources written before the mid-nineteenth century tend to treat this maxim as self-evidently applicable to both written instruments and oral declarations. Modern doctrine, by contrast, largely confines ambiguity canons to written instruments, with separate rules governing oral contracts and testimony. This narrowing is not always visible in older dictionary treatments, creating a potential anachronism trap when applying historical authority to modern disputes.
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Historical Dictionary Support
Burrill's entry is minimalist: it translates the phrase — "in ambiguous discourses" — and immediately redirects the reader to the fuller treatment under "Ambiguus," where the maxim is presented with its canonical application. Burrill also cites Jenkins's *Centuries* (Jenk. Cent. 205) and Broom's *Legal Maxims*, both standard nineteenth-century reference points for the maxim tradition.
The brevity of Burrill's treatment reflects a standard convention in Latin maxim entries of the period: the phrase was considered so well-established among trained lawyers that extended definition was thought unnecessary. This convention creates a gap for modern researchers, who may encounter the phrase without the classical legal education that made the cross-reference intelligible. What Burrill does not supply — and what no comparable single-volume historical dictionary fully provides — is the Roman law lineage of the maxim, which traces to Digest 34.5 and the title *De rebus dubiis*, the classical source for most ambiguity canons that passed into medieval and early modern jurisprudence.
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Jurisdictional Note
The maxim carries greater weight in civil law jurisdictions, where Roman law canons of construction remain closer to the surface of positive law. In common law jurisdictions, the principle survives primarily through *contra proferentem* and the general rule that ambiguous instruments are construed against the drafter, but courts rarely invoke the Latin phrase directly in modern opinions.
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