Definition
ARC does not appear as a standalone legal term of art in the common law tradition. In legal contexts, the word "arc" functions primarily as an ordinary descriptive or geometric term — most often encountered in property law, surveying, and land description, where boundary lines may be described as following the arc of a circle or curve. In metes-and-bounds descriptions, a boundary segment may be defined by its arc length, radius, chord, and central angle, giving "arc" a precise technical meaning in the conveyancing context.
Outside of surveying and property description, "arc" appears in regulatory and safety law (electrical arc flash, arc welding standards) and in older astronomical or navigational instruments referenced in admiralty and maritime contexts (as in the arc of Hadley's quadrant). None of these constitute a distinct legal doctrine or cause of action; the term carries its ordinary geometric or technical meaning into whatever legal field invokes it.
Common Language
Modern common usage (Wiktionary): To move following a curved path; to shape into an arc; to form an electrical arc.
Historical common usage (Webster's 1913): A portion of a curved line, as the arc of a circle or ellipse; a curvature in the shape of a circular arc; the apparent arc described above or below the horizon by the sun or other celestial body.
The legal usage of "arc" in land surveys and metes-and-bounds descriptions tracks the geometric meaning closely but with added precision: a legally operative arc in a deed or plat must typically be defined by at least three of four parameters (arc length, radius, chord bearing, central angle) to be unambiguous. The electrical arc meaning, while important in OSHA and insurance contexts, is an independent technical usage that carries no specialized legal redefinition.
Why It Matters in Research
Researchers are most likely to encounter "arc" as a term of legal consequence in two distinct contexts, and conflating them wastes time.
First, in real property research: when examining historical deeds, survey plats, or title chains, a boundary described as following "the arc of a curve" carries specific surveying requirements. Ambiguity in arc descriptions has generated boundary disputes and quiet title actions. Researchers working with older deeds — particularly 18th and 19th century conveyances — should be alert to imprecise arc descriptions that may have generated later litigation. The relevant legal analysis will be found under boundary law, metes and bounds, and deed construction, not under any entry for "arc" as such.
Second, in regulatory and tort research: "arc flash" and "arc blast" appear in OSHA standards (particularly 29 C.F.R. Part 1910 and Part 1926), workers' compensation claims, and products liability cases involving electrical equipment. Here the term functions as a technical descriptor; the legal analysis turns on negligence, products liability, or regulatory compliance rather than any doctrine specific to the word "arc."
Burrill's Law Dictionary does not contain a substantive entry for "arc." The fragment appearing in the source material is a pagination artifact from an adjacent entry (likely relating to arbitration or a Latin term), not a definition of "arc" itself. Researchers relying on Burrill for this term will find nothing of use.
Historical Dictionary Support
No historical law dictionary in the standard reference shelf — including Burrill, Black, Bouvier, or Tomlin — treats "arc" as an independent legal term warranting its own substantive entry. The absence is informative: "arc" was not a term of art in classical common law pleading, equity, or procedure. Its legal relevance is entirely derivative of the fields (surveying, electrical engineering, astronomy) that use the geometric concept.
The fragment from Burrill's Law Dictionary reproduced in the source material does not define "arc." It appears to be text from an entry on arbitration or a neighboring Latin term, included here due to a scanning or extraction error. Researchers should not treat it as authority for any definition of "arc."
Webster's 1913 and Wiktionary together accurately capture the range of meanings that appear in legal documents wherever "arc" is used. No specialized legal redefinition exists.
Jurisdictional Note
In property law, the legal sufficiency of arc-based boundary descriptions varies by state. Some jurisdictions require all four surveying parameters (arc length, radius, chord, and delta angle) for a curve description to be legally adequate; others accept three. Researchers working on boundary disputes should consult the surveying and conveyancing law of the specific jurisdiction.