\begin{definition}[Definition:Isomorphism Class (Ordered Structures)]
Let $\struct {S, \preccurlyeq}$ be an ordered structure.
Let $\map \II {S, \preccurlyeq}$ be the class of all ordered structures which are order isomorphic to $S$.
Then $\map \II {S, \preccurlyeq}$ is known as the '''isomorphism class''' of $\struct {S, \preccurlyeq}$.
\end{definition}