sigma
sig·ma the eighteenth letter of the Greek alphabet (?, ?, ?)
Origin of sigma
Classical Greeksigma
noun
- The 18th letter of the Greek alphabet. See Table at alphabet.
- A sigma factor.
- Statistics The standard deviation of a given probability distribution or a given set of data.
Origin of sigma
Greek s&imacron;gma, of Phoenician origin; see smk in Semitic roots.Related Forms:
- sig′mate′
adjective
sigma
Noun
(plural sigmas)
- The name for the eighteenth letter of the Classical and Modern Greek, the twentieth letter of Old and Ancient.
- (mathematics) The symbol Σ, used to indicate summation of a set or series.
- (statistics) The symbol σ, used to indicate one standard deviation from the mean, particularly in a normal distribution.