Available Definitions:
1) a. - Of or pertaining to the vertex; situated at the vertex, or highest point; directly overhead, or in the zenith; perpendicularly above one.
2) a. - Perpendicular to the plane of the horizon; upright; plumb; as, a vertical line.
3) n. - Vertical position; zenith.
4) n. - A vertical line, plane, or circle.