Xanthe Terra is a large area on Mars, centered just north of the Martian equator. Its name means "golden-yellow land." It is in the Lunae Palus quadrangle, the Margaritifer Sinus quadrangle, and the Oxia Palus quadrangle. Images from Mars Express, Mars Global Surveyor, and the Mars Reconnaissance Orbiter have revealed ancient river valleys and deltas. (wikipedia entry)
A terra is an extensive land mass. On Mars they are named after the nearest named albedo feature on the Schiaparelli or Antoniadi maps.