zenith sector, n.

zenith-sector
http://www.oed.com/dictionary/zenith-sector_n%3Ftab%3Dmeaning_and_use
Revised 2018

# zenith sectornoun

## Factsheet

### What does the noun zenith sector mean?

There is one meaning in OED's entry for the noun zenith sector. See ‘Meaning & use’ for definition, usage, and quotation evidence.

### How common is the noun zenith sector?

Fewer than 0.01occurrences per million words in modern written English

1770 | 0.0073
1780 | 0.014
1790 | 0.025
1800 | 0.027
1810 | 0.029
1820 | 0.035
1830 | 0.037
1840 | 0.037
1850 | 0.033
1860 | 0.022
1870 | 0.018
1880 | 0.016
1890 | 0.01
1900 | 0.0074
1910 | 0.0054
1920 | 0.0045
1930 | 0.0042
1940 | 0.004
1950 | 0.0042
1960 | 0.0042
1970 | 0.0051
1980 | 0.0054
1990 | 0.0059
2000 | 0.0057
2010 | 0.0056

### Where does the noun zenith sector come from?

Earliest known use

late 1700s

The earliest known use of the noun zenith sector is in the late 1700s.

OED's earliest evidence for zenith sector is from 1775, in Philosophical Transactions.

### Nearby entries

1. Zen garden, n. 1937–
2. zenick, n. 1801–1900
3. zenitfer, n. 1596–
4. zenith, n. & adj. a1387–
5. zenithal, adj.?1731–
6. zenithal projection, n. 1877–
7. zenith-borne, adj. 1865–86
8. zenith distance, n. 1588–
9. zenith line, n. 1585–
10. zenith point, n. 1585–
11. zenith sector, n.1775–
12. zenith sweep, n. 1790–
13. zenith telescope, n. 1803–
14. zenith tube, n. 1825–
15. zenithward, n., adv., & adj. 1655–
16. zenithwards, adv. 1826–
17. Zenker, n.¹ 1872–
18. Zenker, n.² 1894–
19. Zen-like, adj. a1908–
20. Zen master, n. 1907–
21. Zenned-out, adj. 1968–

## Meaning & use

Now historical.

1. 1775–
   A type of zenith telescope formerly favoured, having a heavily built mount with fine adjustments for accurate alignment.
   1. 1775

      > Which quantities are not too small to be measured and demonstrated by an accurate zenith sector, such as that belonging to the Royal Society.

      Philosophical Transactions (Royal Society) vol. 65 499
   2. 1829

      > The zenith sector..can be used only on the meridian; and its measures are referred to the zenith point of the place of observation. Its principal uses are to determine the latitude of the place of observation by a star of known zenith distance; to measure the zenith distance of a star..; and to ascertain the zenith point.

      W. Pearson, Practical Astronomy vol. II. 531
   3. 1970

      > A 5-foot portable zenith sector was found to be difficult both to manipulate and to rectify.

      Notes & Rec. Royal Society vol. 24 266
   4. 2006

      > The expedition was equipped with a 9-foot-tall zenith sector constructed by the London instrument maker George Graham.

      E. Danson, Weighing World iv. 33
   astronomy historical
   1. zenith sector 1775–
      A type of zenith telescope formerly favoured, having a heavily built mount with fine adjustments for accurate alignment.
   2. zenith telescope 1803–
      An astronomical telescope designed to point vertically up to the vicinity of the zenith, used in the precise determination of star positions…
   3. zenith tube 1825–
      A form of zenith telescope; (also) a fixed open tube aligned to the zenith, for projecting the image of the sun when overhead.
   View in Historical Thesaurus

## Frequency

zenith sector typically occurs fewer than 0.01 times per million words in modern written English.

zenith sector is in frequency band 2, which contains words occurring between 0.001 and 0.01 times per million words in modern written English. More about OED's frequency bands

Frequency data is computed programmatically, and should be regarded as an estimate.

### Frequency of zenith sector, n., 1770–2010

* Occurrences per million words in written English

Historical frequency series are derived from Google Books Ngrams (version 2), a data set based on the Google Books corpus of several million books printed in English between 1500 and 2010.

The overall frequency for a given word is calculated by summing frequencies for the main form of the word, any plural or inflected forms, and any major spelling variations.

For sets of homographs (distinct entries that share the same word-form, e.g. mole, n.¹, mole, n.², mole, n.³, etc.), we have estimated the frequency of each homograph entry as a fraction of the total Ngrams frequency for the word-form. This may result in inaccuracies.

Smoothing has been applied to series for lower-frequency words, using a moving-average algorithm. This reduces short-term fluctuations, which may be produced by variability in the content of the Google Books corpus.

Decade | Frequency per million words
--- | ---
1770 | 0.0073
1780 | 0.014
1790 | 0.025
1800 | 0.027
1810 | 0.029
1820 | 0.035
1830 | 0.037
1840 | 0.037
1850 | 0.033
1860 | 0.022
1870 | 0.018
1880 | 0.016
1890 | 0.01
1900 | 0.0074
1910 | 0.0054
1920 | 0.0045
1930 | 0.0042
1940 | 0.004
1950 | 0.0042
1960 | 0.0042
1970 | 0.0051
1980 | 0.0054
1990 | 0.0059
2000 | 0.0057
2010 | 0.0056

Originally published as part of the entry for zenith, n. & adj.

zenith, n. & adj. was revised in June 2018.