\begin{definition}[Definition:Admiralty Mile]
The '''admiralty mile''' is an obsolete British unit of length which was used for air and sea navigation.
It was defined as the average length measured along Earth's surface of one minute of latitude along a meridian, rounded to $4$ significant figures.
{{begin-eqn}}
{{eqn | o = 
      | r = 1
      | c = '''admiralty mile'''
}}
{{eqn | r = 6080
      | c = feet (by definition)
}}
{{eqn | r = 1853 \cdotp 184
      | c = metres
}}
{{eqn | o = \approx
      | r = 1 \cdotp 1515
      | c = (international) mile
}}
{{end-eqn}}
\end{definition}