sigma

[ sig-muh ]

noun

1. the 18th letter of the Greek alphabet: Σ, σ, ς.
2. the consonant sound represented by this letter.

sigma

/ 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

sigma

/ sĭg′mə /

1. A sigma baryon.

Word History and Origins

Origin of sigma¹

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

Word History and Origins

Origin of sigma¹

Greek, of Semitic origin; related to Hebrew samekh

Example Sentences

If you’re lurking in dark corners of the internet, there’s alpha, beta and sigma males.

From Salon

"Our work shows that the dark photon hypothesis is preferred over the standard model hypothesis at a significance of 6.5 sigma, which constitutes evidence for a particle discovery."

From Science Daily

The discrepancy between the two estimates has a statistical significance of five sigma, meaning there is only about a one-in-a-million chance of it being a statistical fluke.

From Scientific American

That was enough to elevate the researchers’ anomalous result to remarkable heights of statistical significance: nearly seven sigma, in the parlance of statistics.

From Scientific American

One is a protein called the sigma-1 receptor, which regulates the release of inflammatory molecules, including several that escalate in people with severe COVID.

From Scientific American