Named after Sir Horace Lamb - British mathematician, physicist (1849-1934).
Lamb is a lunar crater that lies beyond the southeastern limb. It is located in an irregular lunar mare region named Mare Australe, just to the east of the crater Jenner. This crater has a slender inner wall and an interior floor that has been resurfaced by basaltic lava. The rim is somewhat worn and irregular, but retains a generally circular shape and is not overlaid by any smaller craters of significance. (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.