Fontenelle is a lunar crater that is located along the northern edge of Mare Frigoris, in the northern part. To the northeast is the remnant of the crater Birmingham. Due to its location, this crater appears oval in shape when observed from the Earth because of foreshortening. The rim of this crater is generally circular, but the edge is irregular and in some locations has a notched appearance. (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.