Definition
A Latin adjective used in two distinct legal contexts:
1. In the old law of descents: Oblique, cross, transverse, or collateral — designating a line of inheritance that runs sideways rather than directly upward or downward. The opposite of *rectus* (right, straight, or lineal). An obliquus descent is one passing to collateral relatives rather than direct ancestors or descendants.
2. In the law of evidence: Indirect or circumstantial — describing proof that does not establish a fact directly but requires an inferential step to reach the conclusion sought.
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Common Language
Modern common usage (Wiktionary): An obliquus muscle; a muscle running obliquely.
Historical common usage (Webster's 1913): Oblique; slanting; deviating from a right line or the perpendicular.
The common meaning captures the geometric sense of "slanting" or "off-axis," and the legal term carries that same spatial metaphor into legal doctrine — a descent or proof that does not run straight but angles away from the direct line. The anatomical usage in Wiktionary reflects a later narrowing of the term to medical contexts. Researchers encountering obliquus in legal Latin should not rely on the anatomical meaning; the legal senses are distinct and internally consistent with the broader Latin root.
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Common Confusion
Obliquus is sometimes loosely associated with terms like *transversalis* or *collateralis* in descent theory, but these are not interchangeable. *Collateralis* in descent law refers specifically to the collateral line of kindred; *obliquus* is the broader evaluative adjective describing the directional character of the line — any line that is not lineal. The evidence usage (indirect/circumstantial) is entirely independent of the descent usage and should not be conflated: a researcher encountering *obliquus* in a treatise on proof is dealing with a completely different doctrinal context than one encountering it in an inheritance discussion.
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Why It Matters in Research
This is a term found almost exclusively in works of legal Latin — medieval treatises, civilian-influenced texts, and older English legal writing drawing on Roman inheritance theory. Researchers will encounter it most often in two places:
First, in treatises on the law of descents predating the modern codification of inheritance rules. Burrill's citation to Fleta (lib. 5, c. 7, § 2) is significant: Fleta is a 13th-century English legal treatise modeled on Bracton, and the appearance of *obliquus* there places the descent usage firmly in the medieval common law tradition of distinguishing lineal from collateral inheritance. Researchers working with Bracton, Fleta, or Glanvill should expect this term in the context of analyzing who may inherit and by what route.
Second, in evidence scholarship drawing on civilian sources. Burrill's citation to Vinnius (*Jurispr. Contr.* lib. 4, c. 25) points to Arnold Vinnius, the 17th-century Dutch civilian jurist — a reminder that the evidence usage is rooted in Roman and continental procedure rather than English common law tradition. This matters for corpus research: when *obliquus* appears in evidence discussions in English legal texts, the author is often consciously invoking civilian categories.
Because the term has no living English legal usage, it will not appear in modern statutes, regulations, or case law. Its presence in a source is itself a chronological and intellectual signal: the text is either old, is drawing on old sources, or is engaging with the civil law tradition. Researchers should treat *obliquus* as an interpretive clue about the intellectual lineage of the source in which it appears.
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Historical Dictionary Support
All three source dictionaries — both editions of Black's and Burrill — agree precisely on both senses of the term, with no meaningful divergence. This uniformity is expected for a Latin term of art: there is little room for definitional drift when the term belongs to a fixed historical vocabulary rather than an evolving vernacular.
Burrill is the most useful of the three for research purposes because it supplies source citations (Fleta and Vinnius) that the Black's entries omit. Black's (1st and 2nd eds.) condense the definition without attribution, which is adequate for identification but insufficient for tracing the term's doctrinal history.
None of the three source dictionaries explains the relationship between the two senses of the word — the descent usage and the evidence usage — or why both employ the same Latin root. This is a gap in the historical record worth flagging: the connection is the shared metaphor of directness versus indirection, but the legal contexts are otherwise unrelated, and a researcher encountering *obliquus* cold should not assume the senses are doctrinally linked.
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Encyclopedia Cross-Reference
See Law Mind Encyclopedia: Descent and Distribution (historical); Circumstantial Evidence.
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