by Guest » Fri Dec 22, 2006 7:12 pm
I believe you mean "nautical mile."
The generally accepted international value is 1852 m; that value has been used in the US since 1954, although some nations used it since the 1920s.
The origin is as a term to describe 1 minute of arc on the earth's surface, used in navigation, particularly celestril navigation. Since the earth is not a perfect sphere, that value depends on where you measure. Originally, each major sea-going nation had its own value.