The Omicron system was a planetary system. It had at least four planets. The fourth planet, Omicron IV, was inhabited by an intelligent species. 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")