RNDr
Doctor rerum naturalium (Dr. rer. nat.), literally "Doctor of the things of nature", Doctor of Natural Sciences, is a post-graduate academic degree awarded by universities in Europe (e. g. Germany, Austria) to graduates in Chemistry, Biology, Geology, Physics, Mathematics, or similar areas. These doctoral degrees are equivalent to a PhD.
In the Czech Republic (former Czechoslovakia), a similar designated degree, abbreviated RNDr., is awarded, but should not be confused with the Dr. rer. nat., as the RNDr. is only an extension of a master-like degree.