20. The word isotope is Greek, meaning “at the same place,” or at the same position in the periodic table of the elements. Technically, Soddy didn’t come up with the term. It was suggested to him in a conversation in 1913 by a distant relative by marriage, Margaret Todd, M.D. It took eight years for Dr. Todd to do four years of medical school, because during her studies she authored a novel, Mona Maclean, Medical Student, under the pseudonym Graham Travers.