In biology, a genus (plural genera) is a taxon, or taxonomic unit in a hierarchical system, forming the level of classification next above species, grouping individuals together based on similarities between those individuals. In a given genus, its member species share a common ancestor that differs from the common ancestor of the species making up a taxonomic family of related genera.
In binomial nomenclature, the scientific name of an organism is given as genus followed by species. For example, Felis silvestris (the wildcat) and Felis chaus (the jungle cat) are the names of two species within the genus Felis.
The figure at the right illustrates the hierarchy of the various levels.