\begin{definition}[Definition:Signed Area]
Consider the plane region described by a graph in the $xy$-plane.
The '''signed area''' of the region is the area such that:
: The area of the graph on or above the $x$-axis is defined as positive
: The area of the graph below the $x$-axis is defined as negative.
{{explain|As this is a definition which requires the use of spatial relationships, might be good to have a diagram of this.}}
\end{definition}