You searched for: “vertex
vertex, vortex
vertex (VUR teks") (noun)
A point where two lines meet to form an angle; especially, the point on a triangle that is opposite to the base: "Her algebra teacher told her that the vertex of her triangle wasn't correctly calculated."
vortex (VOR teks") (noun)
A mass of spinning air, liquid, etc., that pulls things into its center; sometimes used figuratively: "The exciting tale 'A Descent into the Maelstrom', by Edgar Allan Poe, tells of a ship being pulled down into the vortex of the Maelstrom."

The teacher was caught in the vortex of controversy about the textbook for her geometry classes. There seemed to be a question about the veracity of the formula for calculating the vertex of a triangle.

Word Entries at Get Words: “vertex
The upper surface of the head between the eyes, frons (forehead), and occiput (back part of the head).
This entry is located in the following unit: Ant and Related Entomology Terms (page 24)