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Minute and second of arc

Units for measuring angles

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General referenceInterpretive dossier study · Crown Archives visual atlas
Record originEnglish Wikipedia
Text licenseCC BY-SA 4.0
Source revisionJul 25, 2026
Entity authoritySource title only
Source-derived summary

A minute of arc, arcminute, arc minute, or minute arc, denoted by the symbol ′, is a unit of angular measurement equal to ⁠1/60⁠ of a degree. Since one degree is ⁠1/360⁠ of a turn, or complete rotation, one arcminute is ⁠1/21600⁠ of a turn. The nautical mile (nmi) was originally defined as the arc length of a minute of latitude on a spherical Earth; therefore, the actual Earth's circumference is approximately 21600 nmi. A minute of arc is ⁠π/10800⁠ of a radian.

Editorial summary

Begin with the source’s own compact description: “Minute and second of arc” is units for measuring angles. The dossier treats that line as a proposition to test through Minute, second and Units, not as a finished interpretation.

Editorial reviewA dependable orientation record for establishing vocabulary, names and a first evidence trail. The current 83-word lead offers orientation but no explicit four-digit date, so chronology should not be assumed. The selected authority fields contribute no independent date. For this dossier, Minute, second and Units is the immediate research focus.
Editorial analysis

Why this record matters

The phrase “units for measuring angles” supplies a clear boundary for inquiry. It also exposes the unanswered questions: who defined that boundary, when it became stable and which sources sit outside it.

Evidence profile

The citation trail is more important than the brevity of the summary: it shows where individual claims can be examined in context. The source revision retrieved here is dated Jul 25, 2026.

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Source & attribution

This entry incorporates text from “Minute and second of arc” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.