\begin{definition}[Definition:Celsius]
'''Celsius''' is a temperature scale.
Its two reference points are:
: $0 \cels$, which is set at the melting point of water.
: $100 \cels$, which is set at the boiling point of water, as defined at sea level and standard atmospheric pressure.
A temperature measured in '''Celsius''' is often referred to as so many '''degrees Celsius'''.
\end{definition}