Named after Aleksey Arkhipovich Leonov - Soviet cosmonaut (1934-Live).
Leonov is a small lunar crater that lies to the south of Mare Moscoviense, one of the few maria on the far side. The rim is worn, and several tiny craterlets lie along the edge. The inner walls and interior floor are featureless. (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.