Definition:Hyperbola/Vertex

Parts of Hyperbola

 * HyperbolaParts.png

Consider a hyperbola $K$ whose foci are $F_1$ and $F_2$.

Each of the points where $K$ intersects the major axis of $K$ is known as a vertex of $K$.

In the above diagram, $V_1$ and $V_2$ are the vertices of $K$.

Also see

 * Definition:Covertex of Hyperbola

Linguistic Note
The plural of vertex is vertices.