I'm waiting for the answer
That is the Vertex
A basic pyramid with three sides?
A vertex is the point where three or more edges of a solid figure meet.
A closed three-dimensional figure formed by four or more polygons that intersect only at their edges is called a polyhedron. It contains flat faces, straight edges, and sharp corners or vertices.
a square, a rectangular solid
A vertex on a cube, for example, is where any three edges meet. On a pyramid (square type) it could be at the point on the top or the 4 bottom edges. :)