Kamerlingh Onnes is a lunar crater on the far side. It lies less than a crater diameter to the north-northwest of the crater Kolhörster. North lies Shternberg and to the northwest is Weyl. This is a worn and eroded crater formation that is slightly elongated along the east–west direction, giving it a somewhat oval shape. (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.