Sinus Concordiae (Moon)

"Bay of Harmony"

Sinus Concordiae that lies along the eastern edge of the Mare Tranquillitatis. Along its northern border is an area called the Palus Somni, while the southern border is an area of irregular terrain that contains the ruined crater Da Vinci. (wikipedia entry)

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