Vertical circle
Azimuth Az"i*muth, n. [OE. azimut, F. azimut, fr. Ar. as-sum?t, pl. of as-samt a way, or perh., a point of the horizon and a circle extending to it from the zenith, as being the Arabic article: cf. It. azzimutto, Pg. azimuth, and Ar. samt-al-r[=a]'s the vertex of the heaven. Cf. {Zenith}.] (Astron. & Geodesy) (a) The quadrant of an azimuth circle. (b) An arc of the horizon intercepted between the meridian of the place and a vertical circle passing through the center of any object; as, the azimuth of a star; the azimuth or bearing of a line surveying. [1913 Webster]

Note: In trigonometrical surveying, it is customary to reckon the azimuth of a line from the south point of the horizon around by the west from 0[deg] to 360[deg]. [1913 Webster]

{Azimuth circle}, or {Vertical circle}, one of the great circles of the sphere intersecting each other in the zenith and nadir, and cutting the horizon at right angles. --Hutton.

{Azimuth compass}, a compass resembling the mariner's compass, but having the card divided into degrees instead of rhumbs, and having vertical sights; used for taking the magnetic azimuth of a heavenly body, in order to find, by comparison with the true azimuth, the variation of the needle.

{Azimuth dial}, a dial whose stile or gnomon is at right angles to the plane of the horizon. --Hutton.

{Magnetic azimuth}, an arc of the horizon, intercepted between the vertical circle passing through any object and the magnetic meridian. This is found by observing the object with an azimuth compass. [1913 Webster]

The Collaborative International Dictionary of English. 2000.

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• Vertical circle — Vertical Ver ti*cal, a. [Cf. F. vertical. See {Vertex}.] [1913 Webster] 1. Of or pertaining to the vertex; situated at the vertex, or highest point; directly overhead, or in the zenith; perpendicularly above one. [1913 Webster] Charity . . . is… …   The Collaborative International Dictionary of English

• Vertical circle — Circle Cir cle (s[ e]r k l), n. [OE. cercle, F. cercle, fr. L. circulus (Whence also AS. circul), dim. of circus circle, akin to Gr. kri kos, ki rkos, circle, ring. Cf. {Circus}, {Circum }.] [1913 Webster] 1. A plane figure, bounded by a single… …   The Collaborative International Dictionary of English

• vertical circle — n. Astron. any great circle of the celestial sphere passing through the zenith and the nadir and perpendicular to the horizon …   English World dictionary

• Vertical circle — In astronomy, a vertical circle is a great circle on the celestial sphere that is perpendicular to the horizon. Therefore it passes through the zenith and the nadir. There is a vertical circle for any given direction. The vertical circle which is …   Wikipedia

• vertical circle — A great circle of the celestial sphere passing through the celestial poles as well as the observer’s zenith and nadir. Vertical circles are perpendicular to the horizon. The prime vertical circle, or the prime vertical, passes through the east… …   Aviation dictionary

• vertical circle — /vɜtɪkəl ˈsɜkəl/ (say vertikuhl serkuhl) noun 1. Astronomy a great circle on the celestial sphere which passes through the zenith and cuts the horizon at right angles. 2. Surveying the graduated circular plate of a theodolite used for measuring… …   Australian English dictionary

• vertical circle — noun a great circle on the celestial sphere passing through the zenith and perpendicular to the horizon • Hypernyms: ↑great circle …   Useful english dictionary

• vertical circle — noun Date: 1559 a great circle of the celestial sphere whose plane is perpendicular to that of the horizon see azimuth illustration …   New Collegiate Dictionary

• vertical circle — Astron. a great circle on the celestial sphere passing through the zenith. [1550 60] * * * …   Universalium

• vertical circle — ver′tical cir′cle n. astron. a great circle on the celestial sphere passing through the zenith • Etymology: 1550–60 …   From formal English to slang