zenith tube, n.

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

# zenith tubenoun

## Factsheet

### What does the noun zenith tube mean?

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

### How common is the noun zenith tube?

Fewer than 0.01occurrences per million words in modern written English

1830 | 0.0015
1840 | 0.0017
1850 | 0.0015
1860 | 0.0016
1870 | 0.002
1880 | 0.0021
1890 | 0.0023
1900 | 0.0027
1910 | 0.0035
1920 | 0.0042
1930 | 0.0049
1940 | 0.0054
1950 | 0.0059
1960 | 0.0056
1970 | 0.0051
1980 | 0.0041
1990 | 0.004
2000 | 0.0034
2010 | 0.0024

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

Earliest known use

1820s

The earliest known use of the noun zenith tube is in the 1820s.

OED's earliest evidence for zenith tube is from 1825, in Philosophical Transactions.

### Nearby entries

1. zenith, n. & adj. a1387–
2. zenithal, adj.?1731–
3. zenithal projection, n. 1877–
4. zenith-borne, adj. 1865–86
5. zenith distance, n. 1588–
6. zenith line, n. 1585–
7. zenith point, n. 1585–
8. zenith sector, n. 1775–
9. zenith sweep, n. 1790–
10. zenith telescope, n. 1803–
11. zenith tube, n.1825–
12. zenithward, n., adv., & adj. 1655–
13. zenithwards, adv. 1826–
14. Zenker, n.¹ 1872–
15. Zenker, n.² 1894–
16. Zen-like, adj. a1908–
17. Zen master, n. 1907–
18. Zenned-out, adj. 1968–
19. Zennist, adj. & n. 1904–
20. zeno-, comb. form
21. zenocentric, adj. 1911–

## Meaning & use

Now rare.

1. 1825–
   A form of zenith telescope; (also) a fixed open tube aligned to the zenith, for projecting the image of the sun when overhead.
   1. 1825

      > The first zenith tube was I believe constructed for Dr. Tiarks.

      Philosophical Transactions (Royal Society) vol. 115 174
   2. 1911

      > The series of observations with the Greenwich Reflex Zenith-Tube, starting in 1856 and continued to 1899.

      Monthly Notices Royal Astron. Society vol. 71 541
   3. 2005

      > The first appearance of the noonday sun in the Xochicalco zenith tube occurs exactly fifty-two days before the June solstice.

      C. Ruggles, Ancient Astronomy 188
   astronomy
   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 tube typically occurs fewer than 0.01 times per million words in modern written English.

zenith tube 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 tube, n., 1830–2010

* 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
--- | ---
1830 | 0.0015
1840 | 0.0017
1850 | 0.0015
1860 | 0.0016
1870 | 0.002
1880 | 0.0021
1890 | 0.0023
1900 | 0.0027
1910 | 0.0035
1920 | 0.0042
1930 | 0.0049
1940 | 0.0054
1950 | 0.0059
1960 | 0.0056
1970 | 0.0051
1980 | 0.0041
1990 | 0.004
2000 | 0.0034
2010 | 0.0024

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

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