Definition
In the same terms. A Latin maxim used to indicate that a legal instrument, precedent, provision, or proposition is expressed in identical or precisely equivalent language to another. When two documents, clauses, or authorities are said to be *in isdem terminis*, they share the same operative wording — not merely the same general meaning, but the same specific terms.
The phrase is most commonly encountered in legal argument and judicial reasoning to establish that a prior instrument or authority is directly on point: that the language of the case, deed, statute, or pleading under examination exactly matches a known precedent or form, leaving no room for distinguishing on textual grounds.
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Common Language
This is pure Latin legal jargon with no counterpart in ordinary English usage. The COMMON LANGUAGE section is omitted.
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Why It Matters in Research
Researchers encountering *in isdem terminis* in older cases and treatises should understand it as a precision claim — the writer is asserting textual identity, not merely conceptual similarity. This matters in several research contexts:
**Reading historical cases.** When a court or advocate invokes *in isdem terminis*, it is signaling that a precedent governs not by analogy but by exact correspondence of language. This is a stronger claim than *in pari materia* (on the same subject) or *similis* (similar). A court's rejection of an *in isdem terminis* argument typically turns on a finding that the texts are *not* identical in some operative respect — tracking that dispute is often the key to understanding the holding.
**Deed and conveyancing research.** The phrase appears in property law contexts where the precise wording of covenants, conditions, or grants was compared across instruments. In an era before standardized forms, proving that a prior grant used the exact same terms could determine whether a precedent fully controlled or merely illuminated.
**Pleading.** Early pleading practice emphasized exact verbal replication. *In isdem terminis* was invoked to show that a new pleading conformed to a settled form, or conversely, that a variance from prior pleadings was inconsequential because the terms remained the same.
**Trap for the researcher.** The phrase can be easily confused with *in pari materia* or *in terminis* (which simply means "in express terms" or "precisely"). These are related but distinct. *In isdem terminis* requires identity of language; the others do not. Conflating them in a research memo misrepresents the strength of the textual argument being made.
**Corpus presence.** The phrase is rare in modern legal writing — contemporary courts say "identical language" or "the same terms" — but appears with regularity in nineteenth-century and earlier English and American authorities. Researchers working in that period of the Law Mind corpus should recognize it on sight.
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Historical Dictionary Support
Black's Law Dictionary (2nd Ed.) gives the definition sparsely: "In the same terms," with a single citation to 9 East 487. That citation points to the English King's Bench reporters, consistent with the phrase's heaviest use in English common law practice and its migration into early American legal writing.
The brevity of Black's entry reflects the phrase's status as a working Latin shorthand well understood by practitioners of the era — a term that needed identifying rather than explaining. No substantive elaboration appears in the available historical dictionary sources, which is itself informative: the phrase was transparent to trained readers and did not generate definitional controversy.
What the historical dictionaries miss is the phrase's functional role as a precision marker in legal argument — not just a description of textual equivalence, but an assertion designed to foreclose distinctions. That argumentative function is recoverable only from reading the phrase in context within reported cases.
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Jurisdictional Note
The phrase originates in English common law and carried forward into American legal writing through the nineteenth century. It carries no jurisdiction-specific legal meaning — its content is entirely Latin and logical — but its frequency of use is higher in sources from English and early American jurisdictions than in later domestic American authorities.
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