zepto-, comb. form

zepto
http://www.oed.com/dictionary/zepto_combform%3Ftab%3Dmeaning_and_use
First published 2016

# zepto-combining form

## Factsheet

### Where does the combining form zepto- come from?

zepto- is a borrowing from Latin.

Etymons: Latin septi-.

### Nearby entries

1. Zepp, n. 1914–
2. Zepp, v. 1914–
3. Zeppelin, n. 1896–
4. zeppelin, v. 1910–
5. Zeppelined, adj. 1915–
6. Zeppelining, n. 1915–
7. Zeppelinist, n. 1912–
8. Zeppelinistic, adj. 1930–
9. Zeppelinite, n. 1909–
10. zeppole, n. 1835–
11. zepto-, comb. form
12. zeranol, n. 1971–
13. zerda, n. 1780–1860
14. zerk, n. 1926–
15. zero, n. & adj. 1604–
16. zero, v. 1813–
17. zeroable, adj. 1956–
18. zero balance, adj. 1974–
19. zero-base, adj. 1962–
20. zero-based, adj. 1963–
21. zero beat, n. 1920–

## Etymology

### Summary

A borrowing from Latin.
Etymon: Latin septi-.
An arbitrary alteration of classical Latin septi- septi- comb. form1 (compare ‑o‑ connective); so called with reference to the unit being seven orders of magnitude smaller than one thousandth (10−3). Compare yocto- comb. form, and…
An arbitrary alteration of classical Latin septi- septi- comb. form1 (compare ‑o‑ connective); so called with reference to the unit being seven orders of magnitude smaller than one thousandth (10−3). Compare yocto- comb. form, and also yotta- comb. form, zetta- comb. form.

### Notes

The unit prefix was officially accepted by the General Conference on Weights and Measures in 1991. On the further background compare:

1. 1994

   > In 1990 the International Union of Pure and Applied Chemistry..offered for discussion a suggestion for sepo and oco, from Latin septo, seven and octo, eight. Because the symbol s for sepo would be the same as the symbol for the second, while the symbol o for oco could be misread as a zero, these eventually became zepto (10−21) and yocto (10−24).

   Quarterly Journal Royal Astron. Society vol. 25 570

## Meaning & use

1. Prefixed to the names of units of measurement to denote a factor of 10−21 (one thousand million million millionth; one thousandth to the power of seven), as zeptogram, zeptosecond, etc. Symbol z. Also: forming corresponding adjectives, as zeptomolar.
   1. 1991

      > After further discussion along this line the CCU decided as follows:..10−21 zepto [symbol] z... 10−24 yocto [symbol] y.

      Rapport de la 10e Session, Commité Consultatif des Uniés (Bureau Internat. des Poids et Mesures) u44
   2. 1994

      > The elementary charge is 1.6 x 10−19 coulombs (160 zeptocoloumbs) and the mass of a proton is 1.7 yoctograms.

      New Scientist 3 December 81/2
   3. 2000

      > A unit density particle of 2nm diameter weighs a zeptogram.

      Adv. Chromatrography vol. 40 281
   4. 2001

      > The signal is then detected (limit in the low zeptomolar range) by the two detectors of the Odyssey IR Imager.

      Scientist (Nexis) 14 May 20
   5. 2011

      > Even bandwidth-limited x-ray pulses are not sufficiently short to resolve motion within nuclei that occurs even faster on the time scale of zeptoseconds.

      S. P. Hau-Riege, High-intensity X-rays vi. 159

## Pronunciation

Stress is usually determined by a subsequent element and vowels may be reduced accordingly. Some degree of stress is usually maintained on the first syllable, e.g. zeptosecond

### British English

/ˈzɛptə(ʊ)ˌsɛknd/
ZEP-toh-seck-uhnd

### U.S. English

/ˈzɛptoʊˌsɛk(ə)n(d)/
ZEP-toh-seck-uhnd

####

##### 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.

####

##### Consonants

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

* /d/ also represents a 'tapped' /t/ as in

Some consonants can take the function of the vowel in unstressed syllables. Where necessary, a syllabic marker diacritic is used, hence /ˈpɛd(ə)l/ but /ˈpɛdl̩i/.

##### Vowels

- ifleece, happy
- ɪkit
- ɛdress
- ætrap, bath
- ɑlot, palm, cloth, thought
- ɑrstart
- ɔcloth, thought
- ɔrnorth, force
- ʊfoot
- ugoose
- əstrut, comma
- ərnurse, letter
- ɪ(ə)rnear
- ɛ(ə)rsquare
- ʊ(ə)rcure
- eɪface
- aɪpride
- aʊmouth
- oʊgoat
- ɔɪvoice
- ɑ̃gratin
- æ̃salon
- 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.

####

Simple text respell breaks words into syllables, separated by a hyphen. The syllable which carries the primary stress is written in capital letters. This key covers both British and U.S. English Simple Text Respell.

##### Consonants

b, d, f, h, k, l, m, n, p, r, s, t, v, w and z have their standard English values

- gguy
- jjay
- yyore
- chchore
- khloch
- shshore
- ththaw
- dhthee
- zhbeige

##### Vowels

- atrap
- ahpalm
- airsquare
- arstart
- arrcarry (British only)
- awthought
- ayface
- a(ng)gratin
- edress
- eefleece
- eerdeer
- errmerry
- ikit
- ighpride
- irrmirror
- olot (British only)
- ohgoat
- oogoose
- oorcure
- orforce
- orrsorry (British only)
- owmouth
- oyvoice
- o(ng)salon
- ustrut
- uhletter
- urnurse
- urrhurry
- uufoot

zepto-, comb. form was first published in September 2016.

zepto-, comb. form was last modified in December 2024.