Named after Hermann Oberth - Austrian space scientist (1894-1989).
Oberth is a crater on the far side. It lies in the high northern latitudes, to the southeast of the crater Gamow. To the east is Avogadro. This is a slightly eroded crater with a roughly circular but uneven outer rim. (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.