Order (biology)

In scientific classification used in biology, the order (Latin: ordo, plural ordines) is a taxonomic rank between class and family. The superorder is a rank between class and order. Exact details of formal nomenclature depend on the Nomenclature Code which applies.

History of the concept
The order as a distinctive rank of biological classification having its own distinctive name (and not just called a higher genus (genus summum)) was first introduced by a German botanist, Augustus Quirinus Rivinus in his classification of plants (of treatises in the 1690s). Carolus Linnaeus was the first to apply it consistently to the division of all three kingdoms of Nature (minerals, plants, and animals) in his Systema Naturae (1735, 1st. Ed.).

In French botanical publications, from Michel Adanson's Familles naturelles des plantes (1763) and until the end of the 19th century, the word famille (plural: familles) was used as a French equivalent for this Latin ordo. This equivalence was explicitly stated in the Alphonse De Candolle's Lois de la nomenclature botanique (1868), the precursor of the currently used International Code of Botanical Nomenclature.

In the first international Rules of botanical nomenclature of 1906 the word family (familia) was assigned to the rank indicated by the French "famille", while order (ordo) was reserved for a higher rank, for what in the nineteenth century had often been named a cohors (plural cohortes).

Zoology
In zoology, the Linnaean orders were used more consistently. That is, the orders in the zoology part of the Systema Naturae refer to natural groups. Some of his ordinal names are still in use (e.g. Lepidoptera for the order of moths and butterflies, or Diptera for the order of flies, mosquitoes, midges, and gnats).