Coronavirus is a kind of virus. Some of the many strains of the common cold are coronaviruses, so are COVID-19 and MERS. Flus are their own kind of virus, “influenza viruses”, but I only know what I know from quick conversations with actual biologists, so take it with a grain of salt. I don’t know whether taxonomy is necessarily helpful here. Some frogs are poisonous, some are delicacies, and they come in all sorts of colors, abilities, and sizes.