A related group of species are put together to form a taxon called
A genus is a taxonomic rank used in the biological classification of living and fossil organisms in biology. In the hierarchy of biological classification, genus comes above species and below family. In binomial nomenclature, the genus name forms the first part of the binomial name for each species.
e.g., Felis leo - where Felis indicates a genus of cats from the family Felidae.