Asclepi is a heavily worn lunar crater that lies in the rugged southern highlands. The outer rim has been worn down and rounded by many millions of years of subsequent impacts, so that it is now nearly level with the surrounding terrain. As a result, the crater is now little more than a depression in the surface. The interior is nearly flat and featureless. (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.