An eponym is a word or name for a thing or process or observable which is derived from the name of the person who discovered it, founded it, created it, diagnosed it, etc.

Thus, the dictionary denotes that the English Quaker William Penn (1644-94) is the eponym of the state of Pennsylvanica, since it was founded in his name.

My medical terms, espcially diseases, are name for creators or diagnosticians, as in