geographical mile

English

Alternative forms

• geographic mile

Noun

geographical mile (plural geographical miles)

1. A unit of length corresponding to exactly one minute of arc (1/60 degree) along the Earth's equator, about 1855.4 meters, 2029.1 yards, or roughly 8/7 miles.
   • 1700 February 27, Isaac Newton, letter:

     A geographical mile I call ye sixtith part of a degree of a great circle upon the earth & these miles upon ye body of the Moon in her mean distance from us answer to seconds.

   The equator is exactly 21,600 geographical miles long, about 40,075 km or 24,901 miles.

2. (now inexact) Synonym of nautical mile, exactly 1,852 meters.

References

• “geographical mile, n.”, in OED Online ⁠, Oxford, Oxfordshire: Oxford University Press, launched 2000.