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international nautical mile

In concept, the length of one angular minute of a meridian.

In 1928, the International Hydrographic Conference in Monaco defined¹ the international nautical mile as exactly 1,852 meters, about 6,076.115 49 feet. Symbol², M or NM.

1. International Hydrographic Bureau.
Abridged Manual of the Symbols and Abbreviations Used on Charts.
Special Publication 22.
Monaco, 1928.

Hydrographic Review, volume 5, page 227 (1928).

2. See the discussion on page 11 of
BIPM. Consultative Committee for Units (CCU).
Report of the 16th meeting (13-14 May 2004) to the International Committee for Weights and Measures.