Noah Webster's Dictionary 1. (a.) Perpendicular to the plane of the horizon; upright; plumb; as, a vertical line. 2. (a.) of or pertaining to the vertex; situated at the vertex, or highest point; directly overhead, or in the zenith; perpendicularly above one. 3. (n.) Vertical position; zenith. 4. (n.) A vertical line, plane, or circle.

Multi-Version Concordance Vertical (1 Occurrence) Amos 7:7 Thus he showed me and behold, the Lord stood beside a wall made by a plumb line, with a plumb line in his hand. (See NAS)