Sigma (disambiguation)

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

Sigma may also refer to:

Companies and organizations

 * 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

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
 * 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

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
 * $$\Sigma^0_n$$ or $$\Sigma^1_n$$, sets in the analytical hierarchy
 * $$\Sigma^P_i$$, a set in the polynomial hierarchy
 * Harish-Chandra's σ function
 * Weierstrass sigma function
 * Sigma additivity

Music

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

Places

 * 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

Products

 * 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

Science

 * 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

Sport

 * 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

Video games

 * 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

Other

 * 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