sigma

Ancient Greek alphabet

← rho		→ tau
Σ σ ς Ancient Greek: σίγμα
Wikipedia article on sigma

From Ancient Greek σῖγμα (sîgma), probably from the root σῑγ- (sīg-) as seen in σίζω (sízō, “to hiss”) + -μα (-ma, nominal suffix).^[1][2]

• IPA^(key): /ˈsɪɡmə/

• Audio (US):

  (file)

• Rhymes: -ɪɡmə

sigma (plural sigmas or sigmata)

1. The eighteenth letter of the Classical and Modern Greek alphabets (Σ,  σ), the twentieth letter of Old and Ancient.
   • "Herodotus: On The Customs of the Persians", I.139:

     Their names, which are expressive of some bodily or mental excellence, all end with the same letter---the letter which is called San by the Dorians, and Sigma by the Ionians.

2. (mathematics) The symbol Σ, used to indicate summation of a set or series.
3. (statistics) The symbol σ, used to indicate one standard deviation from the mean, particularly in a normal distribution.
   • 2011, Paul Rincon, (bbc.co.uk) LHC: Higgs boson 'may have been glimpsed'

     None of the spikes seen by the experiments is at much more than the "two sigma" level of certainty.
     A level of "five sigma" is required to claim a discovery, meaning there is less than a one in a million chance the data spike is down to a statistical fluke.

4. (Internet slang) A sigma male (a self-reliant and assertive male).

• (Greek-script letter names) alpha, beta, gamma, delta, epsilon, zeta, eta, theta, iota, kappa, lambda, mu, nu, xi, omicron, pi, rho, sigma, tau, upsilon, phi, chi, psi, omega

sigma (comparative more sigma, superlative most sigma)

1. (Internet slang) Possessing characteristics of a sigma male.

• Magis., agism, migas

Learned borrowing from Latin sigma.

• IPA^(key): (Central, Balearic) [ˈsiɡ.mə]
• IPA^(key): (Valencia) [ˈsiɡ.ma]

sigma f (plural sigmes)

1. Sigma; the Greek letter Σ (lowercase σ or ς)
2. (anatomy) sigmoid colon

• sigmàtic
• sigmatisme

• sigmoide

• “sigma” in Diccionari normatiu valencià, Acadèmia Valenciana de la Llengua.

sigma n or f

1. sigma

when feminine:

Indeclinable when neuter.

From Ancient Greek σῖγμα (sîgma).

• IPA^(key): /ˈsɪx.maː/

• Audio:

  (file)

• Hyphenation: sig‧ma

sigma f (plural sigma's, diminutive sigmaatje n)

1. sigma (letter of the Greek alphabet)

• sigma on the Dutch Wikipedia.Wikipedia ^nl

< Ancient Greek σίγμα (sígma)

Greek letter

Σσ	Previous:	rhoo
	Next:	tau

• IPA^(key): /ˈsiɡmɑ/, [ˈs̠iɡmɑ̝]
• Rhymes: -iɡmɑ
• Syllabification^(key): sig‧ma
• Hyphenation^(key): sig‧ma

sigma

1. sigma (Greek letter)
2. (Internet slang, neologism, often humorous) short for sigma-uros

• “sigma”, in Kielitoimiston sanakirja [Dictionary of Contemporary Finnish]‎^[1] (in Finnish) (online dictionary, continuously updated), Kotimaisten kielten keskuksen verkkojulkaisuja 35, Helsinki: Kotimaisten kielten tutkimuskeskus (Institute for the Languages of Finland), 2004–, retrieved 3 July 2023

• IPA^(key): /siɡ.ma/

• Audio (France (Lyon)):

  (file)

sigma m (invariable)

1. sigma (Greek letter)

• “sigma”, in Trésor de la langue française informatisé [Digitized Treasury of the French Language], 2012

sigma n (genitive singular sigma, nominative plural sigmu) or rarely
sigma f (genitive singular sigmu, nominative plural sigmur)

1. sigma (Greek letter)

or rarely

From Ancient Greek σῖγμα (sîgma), σίγμα (sígma).

• IPA^(key): /ˈsiɡ.ma/
• Rhymes: -iɡma
• Hyphenation: sìg‧ma

sigma m or f (invariable)

1. sigma, specifically:
   1. the name of the Greek-script letter Σ/σ, ς
   2. (mathematics) the symbol Σ, used to indicate summation of a set or series
   3. (statistics) the symbol σ, used to indicate one standard deviation from the mean, specifically in a normal distribution

• sigmatismo/sigmacismo

sigma m (invariable)

1. (anatomy) sigmoid colon

• sgami

Learned borrowing from Ancient Greek σῖγμα (sîgma), from Phoenician 𐤔 (š‬ /⁠šīn⁠/).

• IPA^(key): /ˈsiɡ.ma/

• Audio:

  (file)

• Rhymes: -iɡma
• Syllabification: sig‧ma

sigma f

1. sigma (Greek letter Σ, σ/ς)
2. (mathematics) sigma (symbol Σ, used to indicate summation of a set or series)

• sigma in Polish dictionaries at PWN

sigma m (plural sigmas)

1. sigma (name of the Greek letter Σ, σ)

• “sigma”, in Dicionário Aulete Digital (in Portuguese), Rio de Janeiro: Lexikon Editora Digital, 2008–2026
• “sigma”, in Dicionário Priberam da Língua Portuguesa (in Portuguese), Lisbon: Priberam, 2008–2026

Borrowed from Ancient Greek σῖγμα (sîgma) or French sigma.

sigma m (plural sigma)

1. sigma (Greek letter)

• IPA^(key): /ˈsiɡma/ [ˈsiɣ̞.ma]

• Audio (Costa Rica):

  (file)

• Rhymes: -iɡma
• Syllabification: sig‧ma

sigma f (plural sigmas)

1. sigma; the Greek letter Σ, σ

• “sigma”, in Diccionario de la lengua española [Dictionary of the Spanish Language] (in Spanish), online version 23.8.1, Royal Spanish Academy [Spanish: Real Academia Española], 15 December 2025