Lacus Perseverantiae (Moon)

"Lake of Perseverance"

Lacus Perseverantiae is a small lunar mare extending westward from the northwestern exterior of the crater Firmicus, with smaller extensions to the northeast and northwest at the eastern terminus. Its name is Latin for Lake of Perseverance. (wikipedia entry)

A lacus is a "lake" or small plain. On the Moon they are named after latin terms describing weather and other abstract concepts.