Definition:Right Circular Cone/Axis
Let $K$ be a right circular cone.
Let point $A$ be the apex of $K$.
Then the line $AO$ is the axis of $K$.
In the words of Euclid:
- The axis of the cone is the straight line which remains fixed and about which the triangle is turned.
The plural of axis is axes, which is pronounced ax-eez not ax-iz.