Sigma
Astronomical nomenclature

 Sigma X, a planet
 Sigma Antares sector
 Sigma Draconis star system
 Sigma Draconis I, a planet
 Sigma Draconis II, a planet
 Sigma Draconis III, a planet
 Sigma Draconis III native, a species
 Sigma Draconis IV, a planet
 Sigma Draconis IV native, a species
 Sigma Draconis IV Tourist Center
 Sigma Draconis V, a planet
 Sigma Draconis VI, a planet
 Sigma Draconis VI native
 Sigma Draconis VI natives, a species
 Sigma Draconis VII, a planet
 Sigma Draconis VIII, a planet
 Sigma Draconis IX, a planet
 Sigma Erandi system (aka Sigma Erani system)
 Sigma III solar system
 Quadra Sigma III, a planet
 Sigma Iotia, a star system
 Sigma Iotia II, a planet
 Sigma Nelvana, a star
 Sigma Nesterowitz, a location
 Sigma Tama IV, a planet
 Sigma Trotti, a location

Security terms
 Sigma 9 clearance, a top-level security clearance
 "Tuvok-Sigma-4", authorization code

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