Omicron
Astronomical nomenclature
 Alpha Omicron system
 Alpha Omicron asteroid belt
 Alpha Omicron VII, a planet
 Omicron Ceti, a star
 Omicron Ceti III (aka Omicron III), a planet
 Omicron colony
 Omicron Ceti III inhabitants
 Omicron Delta region
 Omicron Leonis, a star
 Omicron Pascal, a location
 Omicron Theta star system
 Omicron Theta, a planet
 Omicron Theta colony (aka Omicron Theta outpost)
 Omicron Theta colony inhabitants
 Omicron system
 Omicron IV, a planet
 Theta Omicron IV, a planet
 Vega-Omicron sector

Chemistry
 Omicron band
 Omicron particle / omicron radiation

Starfleet terminology
 "Omicron-omicron-alpha-yellow-daystar 2-7", a Starfleet command authorization code in 2365
 "Omicron theta", a subspace sensor band

Retconned references
 Omicron Alpha
 Omicron Beta

fr:Omicron