A taxonomic level of natural history classification. It describes a group of organisms similar in essential features, capable of mating* with members of opposite sex to produce fertile offspring.
In nomenclature, the genus is generally capitalized; the species is in lower case.
* Excluding infertile individuals of the species.
It may also be used in reference to members of a class of molecules (i.e. reactive oxygen species).
More general terms
- Stedman's Medical Dictionary 27th ed, Williams & Wilkins, Baltimore, 1999