Named after Philippus Aureolus Theophrastus Bombast von Hohenheim Paracelsus - Swiss-German doctor, chemist (1493-1541).
Paracelsus is an impact crater. It is located to the east of the crater Barbier, and to the southwest of the large walled plain Vertregt. To the south is the Mare Ingenii, one of the few lunar maria on the far side. This is a circular crater with the smaller Paracelsus Y intruding into its northwestern rim. (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.