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 upright 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. (a) (Dialing) A line perpendicular to the horizon. (b) (Conic Sections) A right line drawn on the vertical plane, and passing through the vertex of the cone. (c) (Surv.) The direction of a plumb line; a line normal to the surface of still water. (d) (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. (a) (Conic Sections) A plane passing through the vertex of a cone, and through its axis. (b) (Projections) Any plane which passes through a vertical line. (c) (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.
[Cf. F. vertical
. See Vertex
Vertical position; zenith. [1913 Webster]
A vertical line, plane, or circle. [1913 Webster]
Prime vertical, Prime vertical dial
. See under Prime, a.
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verticality, erectness, perpendicularity, right angle, normal, azimuth circle, wall, precipice, cliff, elevation, erection, square, plumb line, plummet, vertical
, upright, erect, perpendicular, plumb, normal, straight, bolt, upright, rampant, standing up, rectangular, orthogonal, vertically, up, on end, up on end, right on end, a plomb, endwise, one one's legs, at right angles.