A world in the antimatter universe located in the same galactic position as Earth's, visited by the crew of the U.S.S. Enterprise on stardate 6770.3. Because of the reversed direction of time in the antimatter universe, "Arret" is a backward spelling of "Terra," an alternate name of Earth. The home and laboratory of Karla Five, the Arretian woman who assisted in the Enterprise's escape from the antimatter universe, were located on Arret.