\begin{definition}[Definition:Cartesian Plane/Quadrants/Third]
:400px
Quadrant $\text{III}: \quad$ The area below the $x$-axis and to the left of the $y$-axis is called '''the third quadrant'''.
That is, '''the third quadrant''' is where both the $x$ coordinate and the $y$ coordinate of a point are negative.
\end{definition}