\begin{definition}[Definition:Imperial/Volume/Tun]
The '''tun''' is an imperial unit of volume.
{{begin-eqn}}
{{eqn | o = 
      | r = 1
      | c = '''tun'''
}}
{{eqn | r = 2
      | c = pipes
}}
{{eqn | r = 1 \cdotp 16379 \, 904
      | c = cubic metres
}}
{{eqn | r = 1 \, 163 \cdotp 79904
      | c = litres
}}
{{end-eqn}}
\end{definition}