The Omicron system was an inhabited star system. Crew members aboard Federation starships used the primary Omicron as a reliable point when computing distances between astronomical locations.

Lieutenant Commander Data often told an "amusing" anecdote concerning how he computed the distance between the Omicron system and the Crab Nebula. (TOS: "Assignment: Earth", TNG: "Manhunt")

• Omicron (primary)
  • Omicron I
  • Omicron II
  • Omicron III
  • Omicron IV