Seyfert is a prominent lunar impact crater on the far side. It lies behind the eastern limb , to the east of the crater Espin. Just to the north is the crater Harriot and equally close to the south is Polzunov. The outer rim of this crater is slightly elongated to the north, and the northeastern rim is overlain by the satellite crater Seyfert A. (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.