Skip to the word

Added 9 October 2026

sigma

/ˈsɪɡmə/ noun

noun Definition from Wiktionary (CC BY-SA). Pronunciation from Wiktionary, via Kaikki.org. More about sigma at Wordnik → Where our words come from →

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.

adjective

Possessing characteristics of a sigma male.

Origin

From Ancient Greek σῖγμα (sîgma), probably from the root σῑγ- (sīg-) as seen in σίζω (sízō, “to hiss”) + -μα (-ma, nominal suffix).

From Wiktionary, via Kaikki.org (CC BY-SA)

Back to today's word