Tharsis Montes (Mars)

This feature is named after an earlier feature.

The Tharsis Montes are three large shield volcanoes in the Tharsis region of the planet Mars. From north to south, the volcanoes are Ascraeus Mons, Pavonis Mons and Arsia Mons. Mons is the Latin word for mountain. It is a descriptor term used in astrogeology for mountainous features in the Solar System. (wikipedia entry)

A mons is a mountain. On Mars they are named after the nearest named albedo feature on the Schiaparelli or Antoniadi maps.