Etymologically
Log in

omega

This is the current revision of this entry, as edited by bogdan on 22 October 2026 at 21:33. This address is a permanent link to this version.
Changes in this edit History

Pronunciation

  • UK: /ˈəʊ.mɪ.ɡə/, /əʊˈmiː.ɡə/[1]
  • US: /oʊˈmeɪ.ɡə/, /oʊˈmɛɡ.ə/[1]

Etymology

It is partly borrowed from Late Latin omega and partly its source, Ancient Greek ὦ μέγα (ô méga, “great O”),[2][3][4] made of ὦ (ô), the letter, and μέγα (méga), the neuter of μέγας (mégas, “great”),[2][5][3] from Proto-Indo-European *meg- (“great”).[5][3] It was so called because it stood for a long vowel, in contrast with omicron, "little O".[3][4][2] Barnhart and Etymonline describe it as Medieval Greek, although the name itself is classical.[4][3] Skeat relates the Greek adjective to mickle.[6]

Earliest recorded meaning

The last of a series, the end or final development, chiefly in contrast with alpha: a1398, in John Trevisa's translation of Bartholomaeus Anglicus.[2] Etymonline and Barnhart date the word to about 1400.[3][4]

Semantic evolution

The figurative use comes from the Book of Revelation, where God is "Alpha and Omega, the beginning and the ending";[7][3] Weekley quotes the early English rendering "I am alpha and oo, the bigynnyng and endyng".[8] The word is recorded as the name of the Greek letter only from 1599 in the OED (the early 16th century in the Shorter Oxford).[2][9] Johnson (1755) called it simply the last letter of the alphabet, "therefore taken in the Holy Scripture for the last".[7] Astronomers have used it since 1754 to name the 24th star of a constellation.[2] In particle physics it named various hyperons from 1953, then a neutral meson (1961) and the negatively charged omega minus (1962), first in a paper by Murray Gell-Mann.[2] In cosmology it has meant, since 1976, the ratio of the actual density of the universe to the critical density.[2]

Timeline

  • a1398 – the last of a series, the end.[2]
  • 1520s – used figuratively for the last of anything.[3]
  • 1599 – the name of the last Greek letter.[2]
  • 1754 – (astronomy) the 24th star of a constellation.[2]
  • 1961 – (physics) the omega meson.[2]
  • 1962 – (physics) the omega-minus particle.[2]
  • 1976 – (cosmology) the density parameter of the universe.[2]

Modern meaning

Noun

  1. The 24th and last letter of the Greek alphabet (Ω, ω), originally a long open O.
  2. The last of a series; the end, as in alpha and omega, the beginning and the end.
  3. (physics) An omega meson or an omega-minus hyperon.
  4. (cosmology) The ratio of the actual density of the universe to the critical density.

Adjective

  1. (chemistry) Relating to or being the end group or position in a chain, as in omega oxidation.

Word family

  • omega-3 fatty acid
  • alpha and omega

References

  1. ^ a b Wiktionary, the free dictionary, https://en.wiktionary.org
  2. ^ a b c d e f g h i j k l m n Oxford English Dictionary Online (accessed March 2026), Oxford: Oxford University Press
  3. ^ a b c d e f g h Harper, Douglas. Online Etymology Dictionary, https://www.etymonline.com
  4. ^ a b c d Barnhart, Robert K. (1988), The Barnhart Dictionary of Etymology
  5. ^ a b The American Heritage Dictionary of the English Language (online 2024), 5th ed., Boston: Houghton Mifflin Harcourt
  6. ^ Skeat, Walter W. (1911), A Concise Etymological Dictionary of the English Language, new ed., Oxford: Clarendon Press
  7. ^ a b Johnson, Samuel (1755), A Dictionary of the English Language, London; 4th ed. 1773; Johnson's Dictionary Online, ed. Beth Rapp Young et al.
  8. ^ Weekley, Ernest (1921), An Etymological Dictionary of Modern English, London: John Murray
  9. ^ Shorter Oxford English Dictionary on Historical Principles (2002), 5th ed., ed. William R. Trumble and Angus Stevenson, Oxford: Oxford University Press