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.

abrupt acmatic apical arrowlike azimuth circle bluff bold bolt upright breakneck capital chief consummate dead straight direct downright erect even flat head headlong headmost highest horizontal in a line level lineal linear maximal maximum meridian meridional normal orthodiagonal overmost paramount perpendicular plumb plunging precipitous preeminent rampant rapid rearing rectilineal rectilinear right right angle ruler-straight sharp sheer smooth stand-up standing up steep straight straight-cut straight-front straight-side straight-up streamlined summital supreme tip-top top topmost TRUE ultimate unbending unbent unbowed unbroken uncurved undeflected undeviating undistorted uninterrupted unswerving unturned up-and-down upended upmost uppermost upraised upreared upright upstanding vertical circle zenithal