AskDefine | Define zenith

The Collaborative Dictionary

Zenith \Ze"nith\ (?; 277), n. [OE. senyth, OF. cenith, F. z['e]nith, Sp. zenit, cenit, abbrev. fr. Ar. samt-urras way of the head, vertical place; samt way, path + al the + ras head. Cf. Azimuth.] [1913 Webster]
That point in the visible celestial hemisphere which is vertical to the spectator; the point of the heavens directly overhead; -- opposed to nadir. [1913 Webster] From morn To noon he fell, from noon to dewy eve, A summer's day; and with the setting sun Dropped from the zenith, like a falling star. --Milton. [1913 Webster]
hence, figuratively, the point of culmination; the greatest height; the height of success or prosperity. [1913 Webster] I find my zenith doth depend upon A most auspicious star. --Shak. [1913 Webster] This dead of midnight is the noon of thought, And wisdom mounts her zenith with the stars. --Mrs. Barbauld. [1913 Webster] It was during those civil troubles . . . this aspiring family reached the zenith. --Macaulay. [1913 Webster] Zenith distance. (Astron.) See under Distance. Zenith sector. (Astron.) See Sector,
Zenith telescope (Geodesy), a telescope specially designed for determining the latitude by means of any two stars which pass the meridian about the same time, and at nearly equal distances from the zenith, but on opposite sides of it. It turns both on a vertical and a horizontal axis, is provided with a graduated vertical semicircle, and a level for setting it to a given zenith distance, and with a micrometer for measuring the difference of the zenith distances of the two stars. [1913 Webster]

Word Net

zenith n : the point above the observer that is directly opposite the nadir on the imaginary sphere against which celestial bodies appear to be projected [ant: nadir]

Moby Thesaurus

Olympian heights, acme, aerial heights, apex, apogee, authority, authorization, be-all and end-all, blue ribbon, brow, cap, capstone, championship, climax, cloud nine, command, control, crest, crown, culmen, culmination, directorship, dizzy heights, dominion, edge, effectiveness, elevation, eminence, ether, extreme limit, extremity, first place, first prize, headship, heaven, heavens, hegemony, height, heights, high noon, high point, highest, highest pitch, highest point, imperium, influence, jurisdiction, kingship, leadership, lift, limit, lordship, management, mastership, mastery, maximum, meridian, most, mountaintop, ne plus ultra, new high, no place higher, noon, palms, paramountcy, peak, pinnacle, pitch, point, pole, power, presidency, primacy, raise, record, ridge, rise, rising ground, rule, say, seventh heaven, sky, sovereignty, spire, steep, stratosphere, summit, supremacy, sway, tip, tip-top, top, top spot, upmost, upper extremity, uppermost, uprise, utmost, vantage ground, vantage point, vertex, very top

English

Etymology

From senith from cinit from cenit and/or cenit from سمت.

Pronunciation

  • /'zen.iθ/

Noun

  1. Highest point or state; peak.

Synonyms

Antonyms

Translations

point in the sky vertically above a given position or observer
  • Arabic: سَمْت ,ذروة
  • Croatian: zenit
  • Czech: nadhlavník
  • Finnish: zeniitti
  • French: zénith
  • German: Zenit
  • Italian: zenit
  • Japanese: 天頂
  • Polish: zenit , apogeum
  • Portuguese: zênite
  • Spanish: cenit
peak

Translations to be checked

In broad terms, the zenith is the direction pointing directly above a particular location (perpendicular, orthogonal). Since the concept of being above is itself somewhat vague, scientists define the zenith in more rigorous terms. Specifically, in astronomy, geophysics and related sciences (e.g., meteorology), the zenith at a given point is the local vertical direction pointing away from direction of the force of gravity at that location.
For reference, the vertical direction at the given location and pointing in the same sense as the gravitational force is called the nadir.
Zenith is also used for the highest point reached by a celestial body during its apparent orbit around a given point of observation. http://www.merriam-webster.com/dictionary/zenith Often used in this sense about the Sun, it only corresponds to the first concept of zenith for one latitude at a time, and never at all for latitudes outside the tropics.

Origin

The word zenith derives from the inaccurate reading of the Arabic word samt ('path'), pronounced sent, by scribes in the Middle Ages (during the 14th century), in the expression samt arrâs ('path above the head').

Relevance and use

The zenith is used in the following scientific contexts:
  • It serves as the direction of reference for measuring the zenith angle, which is the angular distance between a direction of interest (e.g., a star) and the local zenith, relative to the point for which the zenith is defined.
  • It defines one of the axes of the horizontal coordinate system in astronomy.

Discussion

  • The zenith directions corresponding to three different locations (not on the same vertical direction) are divergent.
  • Strictly speaking, the zenith is only approximatively contained in the local meridian plane because the latter is defined in terms of the rotational characteristics of the celestial body, not in terms of its gravitational field. The two coincide only for a perfectly rotationally symmetric body. On Earth, the axis of rotation is not fixed with respect to the planet (for example due to constant displacements of its fluid components) so that the local vertical direction, as defined by the gravity field, is itself changing direction in time (for instance due to lunar and solar tides).

References

  • Huschke, Ralph E. (1959) Glossary of Meteorology, American Meteorological Society, Boston, Second printing-1970.
  • McIntosh, D. H. (1972) Meteorological Glossary, Her Majesty's Stationery Office, Met. O. 842, A.P. 897, 319 p.
  • Picoche, J. (1992) Dictionnaire Etymologique du Français, Le Robert, Paris, ISBN 2-85036-458-4.
zenith in Arabic: سمت الرأس
zenith in Asturian: Cénit
zenith in Bengali: সুবিন্দু
zenith in Bulgarian: Зенит
zenith in Catalan: Zenit
zenith in Czech: Zenit
zenith in Danish: Zenit
zenith in German: Zenit (Richtungsangabe)
zenith in Estonian: Seniit
zenith in Modern Greek (1453-): Ζενίθ
zenith in Spanish: Cenit
zenith in Esperanto: Zenito
zenith in Basque: Zenit
zenith in French: Zénith (astronomie)
zenith in Scottish Gaelic: Druim an t-saoghail
zenith in Galician: Cénit
zenith in Croatian: Zenit
zenith in Indonesian: Zenith
zenith in Icelandic: Hvirfilpunktur
zenith in Italian: Zenit
zenith in Hebrew: זנית
zenith in Lithuanian: Zenitas
zenith in Hungarian: Zenit
zenith in Dutch: Zenit (astronomie)
zenith in Japanese: 天頂
zenith in Norwegian: Senit
zenith in Norwegian Nynorsk: Senit
zenith in Polish: Zenit (astronomia)
zenith in Portuguese: Zênite
zenith in Romanian: Zenit
zenith in Russian: Небесная сфера#.D0.97.D0.B5.D0.BD.D0.B8.D1.82_.D0.B8_.D0.BD.D0.B0.D0.B4.D0.B8.D1.80
zenith in Slovak: Zenit
zenith in Slovenian: Nadglavišče
zenith in Serbian: Зенит
zenith in Finnish: Zeniitti
zenith in Swedish: Zenit
zenith in Thai: จุดจอมฟ้า
zenith in Vietnamese: Thiên đỉnh
zenith in Turkish: Zenit
zenith in Ukrainian: Зеніт
zenith in Chinese: 天頂
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