Definition:Ellipse/Minor Axis/Semi-Minor Axis

Definition

 * EllipseParts.png

Consider an ellipse $K$.

A semi-minor axis of $K$ is either half of the minor axis of $K$ from its midpoint to its endpoint.

In the above diagram, $b$ is a semi-minor axis of $K$, the line segment whose endpoints are $O$ and $\left({0, b}\right)$.

The other semi-minor axis of $K$ is the line segment whose endpoints are $O$ and $\left({0, -b}\right)$.

Also see

 * Definition:Semi-Major Axis of Ellipse