\begin{definition}[Definition:Equation of Geometric Figure]
Let there be a coordinate system.
Let the variables $\alpha, \beta, \gamma, \ldots$ be used to identify points within that coordinate system.
Let the variables be related to each other by means of an equation.
Then the equations define the set of points which form a geometric figure.
This equation is known as the '''equation of the geometric figure'''.
\end{definition}