sigma

/หˆsษชษกmษ™/

IPA: /S IH1 G M AH0/

noun
  1. 1

    The eighteenth letter of the Classical and Modern Greek alphabets, the twentieth letter of Old and Ancient.

  2. 2

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

  3. 3

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

Source: https://en.wiktionary.org/wiki/sigma