A genus (/ˈdʒiːnəs/, pl. genera) 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 species name for each species within the genus.
E.G., Felis catus and F. silvestris are two species within the genus Felis. Felis is a genus within the family Felidae.
The composition of a genus is determined by a taxonomist. The standards for genus classification are not strictly codified, so different authorities often produce different classifications for genera. There are some general practices used, however, including the idea that a newly defined genus should fulfill these three criteria to be descriptively useful:
- reasonable compactness – a genus should not be expanded needlessly; and
Moreover, genera should be composed of phylogenetic units of the same kind as other (analogous) genera.
noun, plural: genera
(general) A class or group with common attributes.