Mare Vaporum (Moon)

"Sea of Vapors"

Mare Vaporum is a lunar mare located. The lunar material surrounding the mare is from the Lower Imbrian epoch, and the mare material is from the Eratosthenian epoch. The mare lies in an old basin or crater that is within the Procellarum basin. The mare is 245 kilometers in area. (wikipedia entry)

A mare is a "sea" or large circular plain. On the Moon they are named after latin terms describing weather and other abstract concepts.