Associations to the word «Sigma»

Wiktionary

SIGMA, noun. The eighteenth letter of the Classical and Modern Greek, the twentieth letter of Old and Ancient.
SIGMA, noun. (mathematics) The symbol Σ, used to indicate summation of a set or series.
SIGMA, noun. (statistics) The symbol σ, used to indicate one standard deviation from the mean, particularly in a normal distribution.
SIGMA ADDITIVITY, noun. (analysis) Alternative form of σ-additivity
SIGMA BOND, noun. (chemistry) A covalent atomic bond that is rotationally symmetric about its axis.

Dictionary definition

SIGMA, noun. The 18th letter of the Greek alphabet.

Wise words

Words are always getting conventionalized to some secondary meaning. It is one of the works of poetry to take the truants in custody and bring them back to their right senses.
William Butler Yeats