zygosity, n.

zygosity
http://www.oed.com/dictionary/zygosity_n%3Ftab%3Dmeaning_and_use
First published 1986; not fully revised

# zygositynoun

## Earlier version

- zygosity in OED Second Edition (1989)

## Factsheet

### What does the noun zygosity mean?

There are two meanings listed in OED's entry for the noun zygosity. See ‘Meaning & use’ for definitions, usage, and quotation evidence.

zygosity has developed meanings and uses in subjects including

genetics (1950s) physiology (1950s)

#### 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 noun zygosity?

About 0.05occurrences per million words in modern written English

1950 | 0.05
1960 | 0.049
1970 | 0.047
1980 | 0.046
1990 | 0.051
2000 | 0.05
2010 | 0.045

### How is the noun zygosity pronounced?

#### British English

/zʌɪˈɡɒsɪti/

### Where does the noun zygosity come from?

Earliest known use

1950s

The earliest known use of the noun zygosity is in the 1950s.

OED's earliest evidence for zygosity is from 1952, in New Biology.

zygosity is formed within English, by derivation.

Etymons: zygosis n., ‑ity suffix.

### Nearby entries

1. zygon, n. 1886–
2. zygonema, n. 1911–
3. zygoneurous, adj. 1901–
4. zygophiuran, adj. & n. 1892–
5. zygophore, n. 1904–
6. zygophyllaceous, adj. 1887–
7. zygophyte, n. 1885–
8. zygopleura, n. 1883–
9. zygopterid, n. & adj. 1900–
10. zygosis, n. 1880–
11. zygosity, n.1952–
12. zygosome, n. 1905–
13. zygosperm, n. 1880–
14. zygosphenal, adj. 1854–
15. zygosphene, n. 1854–
16. zygosphere, n. 1880–
17. zygospondyline, adj. 1892–
18. zygospore, n. 1864–
19. zygosporic, adj. 1906–
20. zygostat, n. 1623
21. zygostatical, adj. 1656

## Etymology

### Summary

Formed within English, by derivation.
< zygos- (in zygosis n.) + ‑ity suffix.

## Meaning & use

Genetics.

1. 1. a.
      1952–
      The genetic relationship of twins, triplets, etc., in respect of their being either monozygotic or dizygotic.
      1. 1952

         > Instead of exchanging skin between the twin animals whose zygosity it is desired to establish, grafts are being transplanted from both of them to a third, unrelated recipient.

         New Biology vol. 12 42
      2. 1971

         > Before recent developments with marker genes, it was not possible to assign with certainty the zygosity of a substantial proportion of twin pairs.

         Nature 23 July 277/1
      3. 1978

         > The type of twinning and determination of zygosity are given attention.

         Journal of Royal Society of Medicine vol. 71 311/2
      genetics physiology
      1. homozygosity 1916–
         The state or condition of being homozygous; the degree or extent to which an individual is homozygous with respect to its complement of genetic loci.
      2. monozygosity 1928–
         The condition of being monozygotic.
      3. zygosity 1952–
         The genetic relationship of twins, triplets, etc., in respect of their being either monozygotic or dizygotic.
      View in Historical Thesaurus
   2. b.
      1967–
      The degree of genetic similarity between alleles which determines whether an individual is homozygotic or heterozygotic for the characteristic expressed.
      1. 1967

         > Relationship between Rh0(D) zygosity and red cell Rh0(D) antigen content in family members.

         Journal of Clinical Investigation vol. 46 681 (heading)
      2. 1967

         > The members of two families showed a poor correspondence between antibody binding and zygosity.

         Journal of Clinical Investigation vol. 46 681
      3. 1972

         > Efforts have been made to determine HL-A zygosity of unrelated subjects by use of the gene-dose effect.

         Transplantation vol. XIV. 793/1
      genetics
      1. heterozygosity 1912–
         The state or condition of being heterozygous; the degree or extent to which an individual is heterozygous with respect to its complement of genetic…
      2. zygosity 1967–
         The degree of genetic similarity between alleles which determines whether an individual is homozygotic or heterozygotic for the characteristic…
      View in Historical Thesaurus

## Pronunciation

### British English

/zʌɪˈɡɒsɪti/

####

##### Consonants

- ppea
- ttea
- kkey
- bbuy
- ddye
- ɡguy
- tʃchore
- dʒjay
- ffore
- θthaw
- ssore
- ʃshore
- vvee
- ðthee
- zzee
- ʒbeige
- xloch
- hhay
- llay
- ɬrhingyll
- rray
- wway
- jyore
- mmay
- nnay
- ŋsing

Some consonants can take the function of the vowel in unstressed syllables. Where necessary, a syllabic marker diacritic is used, hence /ˈpɛtl/ but /ˈpɛtl̩i/.

##### Vowels

- iːfleece
- ihappy
- ɪkit
- ɛdress
- atrap, bath
- ɑːstart, palm, bath
- ɒlot
- ɔːthought, force
- ʌstrut
- ʊfoot
- uːgoose
- əletter
- əːnurse
- ɪənear
- ɛːsquare
- ʊəcure
- eɪface
- ʌɪpride
- aʊmouth
- əʊgoat
- ɔɪvoice
- ãgratin
- ɒ̃salon
- ᵻ(/ɪ/-/ə/)
- ᵿ(/ʊ/-/ə/)

##### Other symbols

- The symbol ˈ at the beginning of a syllable indicates that that syllable is pronounced with primary stress.
- The symbol ˌ at the beginning of a syllable indicates that that syllable is pronounced with secondary stress.
- Round brackets ( ) in a transcription indicate that the symbol within the brackets is optional.

View the pronunciation model here.

## Frequency

zygosity typically occurs about 0.05 times per million words in modern written English.

zygosity is in frequency band 3, which contains words occurring between 0.01 and 0.1 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 zygosity, n., 1950–2010

* 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
--- | ---
1950 | 0.05
1960 | 0.049
1970 | 0.047
1980 | 0.046
1990 | 0.051
2000 | 0.05
2010 | 0.045

### Frequency of zygosity, n., 2017–2024

* Occurrences per million words in written English

Modern frequency series are derived from a corpus of 20 billion words, covering the period from 2017 to the present. The corpus is mainly compiled from online news sources, and covers all major varieties of World English.

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 corpus.

Period | Frequency per million words
--- | ---
2017 | 0
2018 | 0.0005
2019 | 0.001
2020 | 0.0029
2021 | 0.0037
2022 | 0.0051
2023 | 0.0058
2024 | 0.0068

zygosity, n. was first published in 1986; not fully revised.

zygosity, n. was last modified in December 2024.