The highest point.
Related Terms 
ADJACENT ANGLES
Two angles having a common vertex and lying at opposite ends of a common side

NUN BUOY
An unlighted buoy of which the upper part of the body (above the waterline), or the larger part of the superstructure, has a cone shape with vertex upwards.

COMPOSITE TRACK
A modified greatcircle track consisting of an initial great circle track from the point of departure with its vertex on a limiting parallel of latitude, a parallelsailing track from this vertex along the limiting parallel to the vertex of a final greatcircle track to the destination.

STERADIAN
The supplementary unit of solid angle in the International System of Units, which, having its vertex in the center of a sphere, cuts off an area on the surface of the sphere equal to that of a square with sides of length equal to the radius of the sphere.
