What is the meaning of Sigma?

The eighteenth letter of the Classical and Modern Greek alphabets (Σ,  σ), the twentieth letter of Old and Ancient.

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

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

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

Possessing characteristics of a sigma male.

Sigma; the Greek letter Σ (lowercase σ or ς)

sigmoid colon

sigma

sigma (letter of the Greek alphabet)

sigma (Greek letter)

short for sigma-uros

sigma (Greek letter)

sigma (Greek letter)

sigma, specifically:

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

the name of the Greek-script letter Σ/σ, ς

the symbol Σ, used to indicate summation of a set or series

the symbol σ, used to indicate one standard deviation from the mean, specifically in a normal distribution

sigmoid colon

sigma (Greek letter Σ, σ/ς)

sigma (symbol Σ, used to indicate summation of a set or series)

sigma (name of the Greek letter Σ, σ)

sigma (Greek letter)

sigma; the Greek letter Σ, σ

Source: wiktionary.org