What is "vertical angle"

Vertical \Ver"ti*cal\, a. [Cf. F. vertical. See Vertex.]

1. Of or pertaining to the vertex; situated at the vertex, or highest point; directly overhead, or in the zenith; perpendicularly above one.

   Charity . . . is the vertical top of all religion.
   --Jer. Taylor.

2. Perpendicular to the plane of the horizon; upright; plumb; as, a vertical line. Vertical angle (Astron. & Geod.), an angle measured on a vertical circle, called an angle of elevation, or altitude, when reckoned from the horizon upward, and of depression when downward below the horizon. Vertical anthers (Bot.), such anthers as stand erect at the top of the filaments. Vertical circle (Astron.), an azimuth circle. See under Azimuth. Vertical drill, an drill. See under Upright. Vertical fire (Mil.), the fire, as of mortars, at high angles of elevation. Vertical leaves (Bot.), leaves which present their edges to the earth and the sky, and their faces to the horizon, as in the Australian species of Eucalyptus. Vertical limb, a graduated arc attached to an instrument, as a theodolite, for measuring vertical angles. Vertical line.

   1. (Dialing) A line perpendicular to the horizon.

   2. (Conic Sections) A right line drawn on the vertical plane, and passing through the vertex of the cone.

   3. (Surv.) The direction of a plumb line; a line normal to the surface of still water.

   4. (Geom., Drawing, etc.) A line parallel to the sides of a page or sheet, in distinction from a horizontal line parallel to the top or bottom. Vertical plane.

      1. (Conic Sections) A plane passing through the vertex of a cone, and through its axis.

      2. (Projections) Any plane which passes through a vertical line.

      3. (Persp.) The plane passing through the point of sight, and perpendicular to the ground plane, and also to the picture.

         Vertical sash, a sash sliding up and down. Cf. French sash, under 3d Sash.

         Vertical steam engine, a steam engine having the crank shaft vertically above or below a vertical cylinder.

n. either of two equal and opposite angles formed by the intersection of two straight lines