Vertex

·noun The top, or crown, of the head.

II. Vertex ·noun The zenith, or the point of the heavens directly overhead.

III. Vertex ·noun A turning point; the principal or highest point; top; summit; crown; apex.

IV. Vertex ·noun 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.