Named after Albert Einstein - German-American physicist; Nobel laureate (1879-1955).
Einstein is a large lunar crater that lies along the western limb , making it difficult to observe from the Earth. The visibility of this formation is affected by libration effects, but even under the best conditions not much detail can be observed except from lunar orbit. Nearby craters of note include Moseley just to the north, Dalton along the eastern rim, Vasco da Gama just to the southeast, and Bohr to the south-southeast. The formation Vallis Bohr is visible to the south. (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.