\begin{definition}[Definition:Cartesian Equation]
A '''Cartesian equation''' is an equation defining the locus of a set of points in a Cartesian space.
Such an equation is generally presented in terms of the variables:
:$x$ and $y$ for a $2$-dimensional space
:$x$, $y$ and $z$ for a $3$-dimensional space
:$x_1, x_2, \ldots, x_n$ for a general $n$-dimensional space
\end{definition}