\begin{definition}[Definition:Kleene Closure]
Let $S$ be a set.
The '''Kleene closure''' of $S$, denoted $S^*$, is the set of all ordered tuples in $S$.
The '''Kleene closure''' is endowed with the concatenation operation $*$:
:$\tuple{ S^*, *}$
to form an algebraic structure.
\end{definition}