Dubyago is a lunar crater that lies in the eastern limb , and it appears significantly foreshortened when viewed from the Earth. It lies along the southern shore of the Mare Undarum, to the southeast of the crater Firmicus. This crater has a somewhat worn outer rim which dips down to a low point along the northern rim, and has its maximum altitude along the eastern side. The most notable aspect of this crater, however, is the dark hue of the interior floor which matches the albedo of the lunar mare to the northwest. (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.