sigma

American  

[sig-muh] / ˈsɪg mə /

noun

1. the 18th letter of the Greek alphabet: Σ, σ, ς.

2. the consonant sound represented by this letter.

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sigma British  

/ ˈsɪɡmə /

noun

1. the 18th letter in the Greek alphabet (Σ, σ, or, when final, ς), a consonant, transliterated as S

2. maths the symbol Σ, indicating summation of the numbers or quantities indicated

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sigma Scientific  

/ sĭg′mə /

1. A sigma baryon.

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Etymology

Origin of sigma

First recorded in 1600–10; from Latin, from Greek sígma

Example Sentences

The research was funded by internal grants from Marian University and Sigma Zeta.

From Science Daily • Apr. 2, 2026

Few are as rancorous as what has gone on at Two Sigma.

From The Wall Street Journal • Apr. 1, 2026

Sigma Trust, which runs both schools, declined to comment and referred the BBC back to the local authority.

From BBC • Mar. 30, 2026

Northampton Saints have two state school partnerships which play in the ACE League: Moulton College in Northampton and Sigma Sixth Colchester, located at Philip Morant School and College.

From BBC • Mar. 17, 2026

The names they picked were Freedom 7, Liberty Bell 7, Friendship 7, Aurora 7, Sigma 7, and Faith 7.

From "Flying to the Moon: An Astronaut's Story" by Michael Collins