\begin{definition}[Definition:Domain (Set Theory)/Mapping]
Let $f: S \to T$ be a mapping.
The '''domain''' of $f$ is $S$, and can be denoted $\Dom f$.
In the context of mappings, the '''domain''' and the preimage of a mapping are the same set.
This definition is the same as that for the '''domain''' of a function.
\end{definition}