σ

σ

1. (mathematics, statistics) Standard deviation.
2. (mathematics) Sum of divisors.
3. (mathematics) Braid group algebra.
4. (physics, scattering) Cross section.
5. (materials science) Tensile stress.

   Coordinate term: τ (shear stress)

6. (linguistics, phonology) Syllable.
7. (IPA, obsolete) a labialized alveolar fricative: identified as IPA [θʷ] or [sᶲ], equivalent to Shona ⟨ȿ⟩.

   See also: ƍ

8. (spatial databases) The select operation.
9. (physics) The Stefan-Boltzmann constant.
10. (chemistry) A shielding constant.

• ϲ (s) — lunate sigma
• ς (s) — word-final position

Derived from its majuscule counterpart Σ.

σ • (s) (lowercase, uppercase Σ)

1. Lower-case sigma (σίγμα), the 18th letter of the ancient Greek alphabet. It represented the voiceless alveolar fricative /s/. It is preceded by ρ and followed by τ.

See also sigma

• σ΄, ͵σ
• с, С (Cyrillic)
• ⲥ, Ⲥ (Coptic)

• (Greek-script letters) Α α, Β β, Γ γ, Δ δ, Ε ε, Ζ ζ, Η η, Θ θ, Ι ι, Κ κ, Λ λ, Μ μ, Ν ν, Ξ ξ, Ο ο, Π π, Ρ ρ, Σ σ ς, Τ τ, Υ υ, Φ φ, Χ χ, Ψ ψ, Ω ω
• (non-Classical letters) Ϝ (W) ϝ (w), Ͷ ͷ, Ͱ (H) ͱ (h), Ϻ (S) ϻ (s), Ϟ ϟ, Ϙ (Q) ϙ (q), Ͳ (S) ͳ (s)
• (punctuation) · ;
• (diacritics) ᾿ ῾ ◌́ ◌̀ ῀ ¨

• ς (s) (only at the end of a word)

σ • (s) (lowercase, uppercase Σ)

1. The lower case letter sigma (σίγμα), the 18th letter of the modern Greek alphabet.

• (Greek-script letters) Α α, Β β, Γ γ, Δ δ, Ε ε, Ζ ζ, Η η, Θ θ, Ι ι, Κ κ, Λ λ, Μ μ, Ν ν, Ξ ξ, Ο ο, Π π, Ρ ρ, Σ σ ς, Τ τ, Υ υ, Φ φ, Χ χ, Ψ ψ, Ω ω
• (non-Classical letters) Ϝ (W) ϝ (w), Ͷ ͷ, Ͱ (H) ͱ (h), Ϻ (S) ϻ (s), Ϟ ϟ, Ϙ (Q) ϙ (q), Ͳ (S) ͳ (s)
• (punctuation) · ;
• (diacritics) ᾿ ῾ ◌́ ◌̀ ῀ ¨
• σ΄
• ͵σ