zygomorphous, adj.

zygomorphous
http://www.oed.com/dictionary/zygomorphous_adj%3Ftab%3Dmeaning_and_use
First published 1921; not fully revised

# zygomorphousadjective

## Factsheet

### What does the adjective zygomorphous mean?

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

#### Entry status

OED is undergoing a continuous programme of revision to modernize and improve definitions. This entry has not yet been fully revised.

### How common is the adjective zygomorphous?

Fewer than 0.01occurrences per million words in modern written English

1870 | 0.003
1880 | 0.0028
1890 | 0.0025
1900 | 0.0028
1910 | 0.0028
1920 | 0.0019
1930 | 0.0021
1940 | 0.0017
1950 | 0.0015
1960 | 0.0014
1970 | 0.0007
1980 | 0.0006
1990 | 0.0004
2000 | 0.0001
2010 | 0.0001

### Where does the adjective zygomorphous come from?

Earliest known use

1870s

The earliest known use of the adjective zygomorphous is in the 1870s.

OED's only evidence for zygomorphous is from 1879, in the writing of Asa Gray, botanist.

### Nearby entries

1. zygodont, adj. 1888–
2. zygogenesis, n. 1950–
3. zygology, n. 1970–
4. zygoma, n. 1684–
5. zygomatic, adj. & n. 1712–
6. zygomatico-, comb. form
7. zygomato-, comb. form
8. zygomere, n. 1966–
9. zygomorphic, adj. 1875–
10. zygomorphism, n. 1875–
11. zygomorphous, adj.1879–
12. Zygomycetes, n. 1887–
13. zygomycetous, adj. 1928–
14. zygon, n. 1886–
15. zygonema, n. 1911–
16. zygoneurous, adj. 1901–
17. zygophiuran, adj. & n. 1892–
18. zygophore, n. 1904–
19. zygophyllaceous, adj. 1887–
20. zygophyte, n. 1885–
21. zygopleura, n. 1883–

## Meaning & use

Botany.

1. 1879–
   Opposed to actinomorphous adj.
   Stressed as zygoˈmorphous.
   1. 1879

      > Both these forms [sc. monosymmetrical and polysymmetrical] have a more expressive and older terminology, adopted by Eichler, viz.:—Zygomorphous, for flowers, or other structures, which can be bisected in one plane,..(median zygomorphous, when this is a median or anteroposterior plane,..transverse zygomorphous, when the plane of section is transverse or at right angles to the median).

      A. Gray in A. Gray & G. L. Goodale, Botanical Text-book (ed. 6) vol. I. 175 (note)
   plants
   1. regular 1760–
      Botany. Of a flower, corolla, calyx, etc.: having its parts uniform in form and size; radially symmetric.
   2. decandrous 1808–
      Characterized by ten stamens.
   3. irregular 1826–
      Botany and Zoology. Not having a definite, symmetrical, or uniform shape or arrangement; spec. of a flower, Having the members of the same cycle…
   4. tetramerous 1835–
      Having, consisting of, or characterized by four parts: spec.. Botany. Having the parts of the flower-whorl in series of four. (Often written 4-merous…
   5. hendecagynous 1845–89
      Having eleven pistils.
   6. pentamerous 1848–
      Botany. Having five parts, or parts in groups or multiples of five. (Often written 5-merous.)
   7. symmetrical 1849–
      Botany. Of a flower: Having the same number of parts in each whorl: = isomerous, adj. 1.
   8. hexamerous 1857–
      Botany. Having the parts of the flower-whorl six in number. (Often written 6-merous.)
   9. isomerous 1857–
      Botany. Of a flower: Having the same number of parts in each whorl. (Said also of the whorls.) Opposed to heteromerous, adj. 2b.
   10. octamerous 1857–
       Having parts arranged in groups of eight; having eight parts of a particular type.
   11. anisomerous 1861–
       Not having equal, or the same number of, parts, unsymmetrical; esp. in Bot. having unequal numbers of parts in different whorls.
   12. octomeral 1871–
       Having parts arranged in groups of eight; = octamerous, adj.
   13. hemicyclic 1875–
       Applied to flowers which have the parts arranged spirally in such a manner that the transition from one series to another (e.g. from petals to…
   14. zygomorphic 1875–
       Applied to a flower that is symmetrical about a single plane, i.e. divisible into similar lateral halves in only one way; = monosymmetrical, adj.
   15. haplostemonous 1878–
       (Of a plant or a flower) having a single whorl or row of stamens; cf. diplostemonous, adj.
   16. zygomorphous 1879–
       Opposed to actinomorphous, adj.
   17. tetracyclic 1880–
       Having four cycles or circles; spec. in Botany, having four whorls of floral organs.
   18. heteromerous 1882–
       Botany. Applied to flowers in which the members differ in number in the different whorls: opposed to isomerous.
   19. five-merous 1888–
       = pentamerous, adj.
   20. heterocyclic 1895–
       Botany. = heteromerous, adj. 2b.
   21. oligomerous 1897–
       Botany. Having fewer divisions or parts than normal.
   22. pleiomerous 1898–
       Of a floral whorl or flower: having more than the normal number of parts.
   23. decasepalous
       Having ten sepals.
   View in Historical Thesaurus

## Frequency

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

zygomorphous is in frequency band 1, which contains words occurring fewer than 0.001 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 zygomorphous, adj., 1870–2010

* 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
--- | ---
1870 | 0.003
1880 | 0.0028
1890 | 0.0025
1900 | 0.0028
1910 | 0.0028
1920 | 0.0019
1930 | 0.0021
1940 | 0.0017
1950 | 0.0015
1960 | 0.0014
1970 | 0.0007
1980 | 0.0006
1990 | 0.0004
2000 | 0.0001
2010 | 0.0001

Originally published as part of the entry for zygomorphic, adj.

zygomorphic, adj. was first published in 1921; not fully revised.