the highest point; the summit
in mathematics, the point opposite to and farthest from the base in a figure
in mathematics, the termination or intersection of lines or curves
the vertex of an angle
in mathematics, a point where a main axis of an ellipse, parabola, or hyperbola intersects the curve
= zenith (1)
in anatomy, the top of the head
[Latin vertic-, vertex whirl, whirlpool, top of the head, summit, from vertere to turn]