\begin{definition}[Definition:Knot (Unit of Measurement)]
The '''knot''' is a unit of velocity which is used for air and sea navigation.
It is defined as $1$ '''nautical mile''' per '''hour'''.
It is now defined as exactly $1 \, 852$ metres.
{{begin-eqn}}
{{eqn | o = 
      | r = 1
      | c = '''knot'''
}}
{{eqn | r = 1 \, 852
      | c = metres per hour (exactly)
}}
{{eqn | o = \approx
      | r = 0 \cdotp 51444
      | c = metres per second
}}
{{eqn | o = \approx
      | r = 1 \cdotp 15078
      | c = (international) miles per hour
}}
{{end-eqn}}
\end{definition}