Vertex

A turning point; the principal or highest point; top; summit; crown; apex.

The top, or crown, of the head.

The zenith, or the point of the heavens directly overhead.

The point in any figure opposite to, and farthest from, the base; the terminating point of some particular line or lines in a figure or a curve; the top, or the point opposite the base.

A point where two or more lines meet