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n. The 18th letter of the Greek alphabet. See Table at alphabet.

n. A sigma factor.

n. A sigma baryon.

n. The name for the eighteenth letter of the Classical and Modern Greek, the nineteenth letter of Old and Ancient.

n. The symbol Σ, used to indicate summation of a set or series.

n. The symbol σ, used to indicate one standard deviation from the mean, particularly in a normal distribution.

n. The Greek letter Σ, σ, or ς (English S, or s). It originally had the form of the English C.

n. The name of the Greek letter Σ, σ, ς, equivalent to the English S, s. (For its early forms, see under S.)

n. An S-shaped or sigmoid flesh-spicule of a sponge.

n. The curve of the letter S or any approximate curve.

n. In descriptive biol., one of the S-shaped ridges on the surface of certain molluscan shells, as those of gastropods and cephalopods.

n. In experimental psychology, the time-unit, of a second: abbreviated σ.

n. the 18th letter of the Greek alphabet

""Three sigma" is a manufacturing concept used to control processes, a concept that I am intimately familiar with."

letter    letter of the alphabet    alphabetic character   

sigma function   

within one sigma    sigmalike   

Enigma    enigma    stigma   

rho    lambda    omega    phi    Vega    gamma    nu    eta    muon    delta