Van Biesbroeck is a small lunar impact crater that interrupts the southern rim of the lava-flooded crater Krieger, in the Oceanus Procellarum. The crater is circular and symmetrical, with sloping inner walls that run down to a small interior floor. Van Biesbroeck was designated Krieger B before the IAU gave it a unique name. (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.