Definition
IDO, as it appears in historical legal sources, is an abbreviated or variant form directing the reader to the concept of identity in the law of evidence — specifically, the fact that a subject, person, or thing before a court is the same as it is represented, claimed, or charged to be. The term functions as a truncated citation marker in Burrill's Law Dictionary, pointing toward the fuller treatment of idem and identity rather than standing alone as a discrete legal term of art.
In modern usage, IDO does not appear as a recognized standalone term in American or English legal doctrine. Its appearance in historical legal dictionaries is almost entirely a function of abbreviation conventions common to nineteenth-century legal lexicography, where Latin-derived shorthand was used to compress cross-references and reduce typesetting costs. Researchers encountering "IDO" in historical sources should treat it as an editorial artifact rather than a substantive legal concept.
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Common Language
Modern common usage (Wiktionary): A constructed language; a reform of Esperanto and Idiom Neutral.
Historical common usage (Webster's 1913): An artificial international language selected by the Delegation for the Adoption of an Auxiliary International Language, made public in 1907 and subsequently revised by a permanent committee or Academy.
The gap between common and legal meaning here is absolute rather than merely significant: the common-language term IDO refers entirely to an auxiliary constructed language with no connection to legal doctrine. A researcher encountering IDO in a legal context should not import any ordinary-language meaning from this usage. The appearance of IDO in legal sources is a bibliographic phenomenon, not a shared concept.
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Common Confusion
IDO is easily mistaken for IDEM (Latin: "the same"), which is the substantive legal and logical term governing identity of persons, things, or propositions across legal instruments and proceedings. The confusion is compounded by the fact that historical legal dictionaries frequently used abbreviated forms interchangeably, and printers' conventions sometimes rendered idem as a string that modern readers parse as "ido." Researchers should also distinguish between identity as a matter of evidence — which IDO gestures toward in Burrill — and identity as a matter of contract or pleading, which implicates idem sonans and related doctrines.
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Why It Matters in Research
Researchers working in the Law Mind corpus should treat IDO as a navigational signal rather than a terminus. When Burrill's dictionary uses this form, it is directing the reader to the concept of identity in evidence law — a concept with genuine doctrinal weight that has its own entry structure in the historical literature.
The practical trap: a full-text search for IDO across historical legal sources will return noise from multiple sources, including abbreviated cross-references, typographical artifacts, and the constructed-language usage that became prominent in the early twentieth century. Searches should be filtered by date and context, and any hit should be read in surrounding text before conclusions are drawn.
The underlying doctrine IDO abbreviates — identity in evidence — was a live and contested question in nineteenth-century evidence law, particularly regarding the proof required to establish that a defendant in a criminal case was the same person previously convicted, or that a document produced at trial was the same one described in pleadings. Burrill cites his own Circumstantial Evidence for the developed treatment. Researchers pursuing this thread should move directly to entries on IDENTITY and IDEM rather than attempting to build analysis on the IDO abbreviation itself.
Nothing in the historical record suggests IDO ever achieved independent doctrinal status, was used in judicial opinions as a term of art, or appeared in statutory definitions. Its life is entirely within the abbreviation conventions of nineteenth-century legal lexicography.
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Historical Dictionary Support
Burrill's Law Dictionary is the sole source that surfaces IDO as a legal entry, and even there it functions as a compressed redirect. Burrill cross-references his own Circumstantial Evidence at pages 382, 453, 631, and 644 — pages dealing with sameness and identity as evidentiary facts. The entry does not define IDO as a concept but uses it to collapse the treatment of identity into the surrounding apparatus of the dictionary.
No other major historical legal dictionary — not Black's, not Bouvier's, not Tomlin's — carries IDO as a discrete entry. This absence is itself informative: the term never achieved sufficient independent standing to warrant entry in competing reference works. Burrill's choice to include it reflects his dictionary's more compressed, cross-reference-heavy style rather than any special doctrinal significance.
What the historical sources collectively make clear is that the real conceptual work was always done by IDEM and IDENTITY. Researchers consulting Burrill on IDO are, without exception, being directed to those terms.
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Jurisdictional Note
No known jurisdictional variation attaches to IDO as a term, because it does not function as a substantive legal term in any jurisdiction. The identity-in-evidence doctrine to which it points was developed in both English and American common law courts, with broadly parallel but not identical evidentiary standards across jurisdictions.
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