Mercurius (Moon)

Mercury; Roman mythical messenger.

Mercurius is a lunar impact crater that is located in the northeastern part. It lies to the northeast of the smaller crater Carrington, and west-northwest of Zeno. Just to the south is the small lunar mare named Lacus Spei, and to the west is the larger Lacus Temporis. The rim is circular, with a somewhat irregular edge. (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.