Although it sounds like a Biology term, this comes from nuclear physics. When we're talking about a particular type of atom in Chemistry we are talking about a nucleus and the electrons orbiting it.
But sometimes in Physics we talk exclusively about nuclear reactions i.e. a nucleus changing from one type to another. In this instance we ignore the electrons around the outside of the atom. We tend to use the word "nuclide" at this point, the same way we might refer to different chemical elements, or chemical species. We refer to different nuclides to mean the different nuclei in a process.
Nuclides can turn from one type into another by lots of different routes. Alpha decay, Beta decay, Beta capture etc. These nuclear reactions will generate a new nuclide (a new nuclear species) and they began with other nuclides. They are nuclides generated by other nuclides "nucleo-genic nuclides".
By contrast, some nuclides are made as a result of cosmic rays bombarding a nucleus, creating a new nuclide species. These nuclides are called cosmo-genic nuclides. Nuclides generated by cosmic ray interactions.