\begin{definition}[Definition:Right Circular Cone/Axis]
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Let $K$ be a right circular cone.
Let point $A$ be the apex of $K$.
Let point $O$ be the center of the base of $K$.
Then the line $AO$ is the '''axis''' of $K$.
{{EuclidSaid}}
:''{{Definition:Euclid's Definitions - Book XI/19 - Axis of Cone}}''
{{EuclidDefRefNocat|XI|19|Axis of Cone}}
\end{definition}