Schlüter is a lunar impact crater that is located near the western limb 's near side. It lies along the northwestern face of the Montes Cordillera mountain range that encircles the Mare Orientale. Nearly attached to the eastern rim is the damaged crater Hartwig. Schlüter has an irregular outer rim that is roughly circular, with small outward bulges to the north and southeast. (wikipedia entry)
A crater is a circular depression likely created by an impact event. On the Moon they are named after deceased scientists, polar explorers, astronauts or cosmonauts.