Galen (Moon)

Named after Claudius Galen - Greek doctor (c. 129-200).

Galen is a small lunar impact crater that lies in the rugged region. It is located to the south-southeast of the crater Aratus, a slightly larger formation. Further to the west is the crater Conon, near the flanks of the Montes Apeninnus. (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.