The word "isotopic" refers to things that are related to or have the same number of atoms of each element, but differ in the number of neutrons in their nuclei. Full definition
On the basis of anomalous isotopic compositions of oxygen and magnesium, 14 oxide grains from two primitive meteorites (Bishunpur and Semarkona) have been identified as circumstellar condensates. (science.sciencemag.org)
Atmospheric scientists call this shift the Suess effect, and the change in isotopic ratios of carbon due to fossil - fuel use is easy to see over the last century. (theatlantic.com)
Evidence from isotopic data on Early Holocene bison and other large herbivores in northern Europe. (senckenberg.de)