The Modean system was an inhabited star system.

When Geordi La Forge was a child, he would periodically live with his father or his mother at their respective Starfleet postings. For a time Geordi lived with his father in the Modean system while he was stationed there studying invertebrates. (TNG: "Imaginary Friend")

According to Star Trek: Star Charts ("United Federation of Planets"), there was a planet named Modean, which was presumably located in this system. In 2378, this planet was listed as a Federation member.