Sigma (Σ or σ, word-final lowercase ς) is the 18th letter of the Greek alphabet.

Look up sigma, Sigma, Σ, σ, or ς in Wiktionary, the free dictionary.

Sigma may also refer to:

• Sigma AB, a Swedish IT consultancy company
• Sigma Alimentos, multinational food processing and distribution company
• Sigma Corporation, a Japanese camera and lens manufacturer
• Sigma Designs, Inc., a US semiconductor manufacturer
• Sigma Healthcare, an Australian pharmaceutical company
• Sigma Motor Corporation, a defunct South African motor vehicle assembler and manufacturer
• Sigma Motors, a Pakistani assembler of Land Rovers
• Sigma Sigma Sigma (Tri-Sigma), an American women's sorority centered on education & scholarship
• Sigma Sport, a German manufacturer of electronic sports equipment
• Sigma TV, a television channel in Cyprus
• Sigma (operations research), a company founded in the UK in 1961
• SIGMA (verification service), Nielsen Media Research's tracking system for videos
• Sigma-Aldrich, an American chemical company
• Telkomsigma or Sigma Cipta Caraka, an Indonesian IT company

• Ood Sigma, a fictional character from the Doctor Who series
• Space City Sigma, a 1980s Indian science fiction TV series
• Sigma, a fictional character from the anime Tweeny Witches
• Sigma Society, a fictional Mensa-type club, appearing in the third episode of Columbo sixth season
• Sigma, a fictional character from the Bungo Stray Dogs manga and anime series

• Summation operator forming a series in mathematics Σ
• Standard deviation in statistics σ
• Divisor function in number theory σ
• Sigma-algebra (σ-algebra, σ-field) in set theory
• A busy beaver function in computability theory Σ
• ${\displaystyle \Sigma _{n}^{0}}$ or ${\displaystyle \Sigma _{n}^{1}}$, sets in the analytical hierarchy
• ${\displaystyle \Sigma _{i}^{P}}$, a set in the polynomial hierarchy
• Harish-Chandra's σ function
• Weierstrass sigma function
• Sigma additivity

• Sigma (album)
• Sigma (DJs), a British drum and bass duo
• Sigma AZ (band), punk rock band from Phoenix, Arizona

• Sigma, Capiz, a municipality in the Philippines
• Sigma, Lee County, Virginia, United States
• Sığma, Sarayköy
• The Sigma Plan, to raise the dikes of the Scheldt River in Belgium

• GM Sigma platform, an automobile platform
• Mitsubishi Sigma
• SDS Sigma series of computers from Scientific Data Systems
• Sigma (sailplane)
• Sigma Guitars
• Six Sigma quality management program
• Smith & Wesson Sigma, a firearm

• σ, sigma bond in chemistry
• σ, sigma factor of RNA polymerase in biology
• σ, Stefan–Boltzmann constant of radiation in physics
• σ, stress (mechanics), the force per unit area applied by internal forces of a material
• σ, the electronic substituent constant for activation of substituted arenes in the Hammett equation
• σ, a measure of a material's electrical conductivity ability
• Cross section σ in physics
• Pauli matrices in quantum physics
• Sigma baryon in particle physics
• Sigma receptor, a neural receptor
• Surface charge density in classical electromagnetism
• Sigma, a Greek letter used in Bayer designations for naming stars, in astronomy. Notable examples include:
  • Sigma Canis Majoris
  • Sigma Draconis
  • Sigma Octantis
  • Sigma Orionis

• Sigma FC, a Canadian soccer team
• SK Sigma Olomouc, a Czech association football team
• Histor–Sigma, a Belgian professional cycling team known as Sigma in 1986

• Sigma (Mega Man X), the villain of the Mega Man X series
• Sigma (Overwatch), a hero from Overwatch
• Ninja Gaiden Sigma, a video game
• Sigma, a character in the BioShock 2 video game universe
• Sigma Harmonics, a video game
• Sigma Klim, a major character and protagonist in the Zero Escape video game series
• Sigma, a team on the Dota 2 online video game

• Advance Sigma, a Swiss paraglider design
• Sigma (couch), used in ancient Roman banquets
• Sigma class corvette, a naval ship
• Sigma male, slang term for masculine men

• Sygma (disambiguation)

This disambiguation page lists articles associated with the title Sigma.
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