Sigma (disambiguation)

Sigma (Σ,σ) is a letter of the Greek alphabet.

Sigma may also refer to:

Aviation

• Advance Sigma, a Swiss paraglider design

Companies

• SIGMA (verification service), Nielsen Media Research's tracking system for videos
• Sigma AB, a Swedish IT consultancy company
• Sigma Corporation, a Japanese camera and lens manufacturer
• Sigma Designs, Inc., a US semiconductor manufacturer
• Sigma Motor Corporation, a defunct South African motor vehicle assembler and manufacturer
• Sigma Motors, a Pakistani assembler of Land Rovers
• Sigma (operations research)
• Sigma Pharmaceuticals, an Australian pharmaceutical company
• Sigma Sport, a German manufacturer of electronic sports equipment
• Sigma TV, a television channel in Cyprus
• Sigma-Aldrich, an American chemical company
• Telkomsigma or Sigma Cipta Caraka, an Indonesian IT company

Films and television

• 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

Mathematics

• 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

Places

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

Products

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

Science

• Stefan–Boltzmann constant of radiation in physics σ
• Sigma factor of RNA polymerase in biology σ
• In the Hammett equation, the electronic substituent constant σ for activation of substituted arenes
• Sigma baryon, in particle physics
• Pauli matrices in quantum physics
• Cross section σ in physics
• Sigma bond in chemistry σ
• Sigma receptor, a neural receptor
• Electrical conductivity, a measure of a material's ability to conduct electricity σ
• Surface charge density in classical electromagnetism
• Stress (mechanics), the force per unit area applied by internal forces of a material σ

Video games

• Sigma (Mega Man X), a video game character
• 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
• Sigma, a hero from Overwatch

Other

• Sigma (couch), used in ancient Roman banquets
• Sigma (DJs), a British drum and bass duo
• Sigma AZ (band), punk rock band from Phoenix, Arizona
• Sigma class corvette, a naval ship
• The Six Sigma quality management program
• SK Sigma Olomouc, a Czech association football team
• Histor–Sigma, a Belgian professional cycling team known as Sigma in 1986
• Sigma (album)
• Lone wolf (trait), referred to in humans as the Sigma personality trait

See also

• Sygma (disambiguation)