Scheiner is a lunar impact crater that lies to the west of the enormous walled plain Clavius. To the southeast near the rim of Clavius is the crater Blancanus. The rim is worn, eroded, and marked with multiple impacts. It is most heavily worn in the northern part, where a cluster of craterlets covers the entrance to a low valley leading to the north. (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.