Orions were characterised by their green skin tone, through their skin tone could range from orange to blue. Males were larger than the average human and typically lacked any hair on their heads. Orion females were of a more similar height to other humanoid species. Female Orions where also known to possess powerful pheromones that could greatly influence some other humanoid species. (ENT: "Borderlands", "Bound")
The Orions were known to operate in slavery. They not only sold there own women as Orion slave girls but would prey on other species, kidnapping them to then auction off at a slave market. (ENT: "Borderlands")
The Orions were also responsible for the creation of the Orion syndicate, which by the late-24th century had grown to be very large criminal organisation that spanned across the Alpha and Beta Quadrants.