The largest level of classification of these options is the domain. The domain is the highest level of classification in the taxonomic hierarchy. Domains are divided into smaller groups called kingdoms. Kingdoms are further divided into phyla (or divisions in some classifications). Phyla (divisions) are then divided into classes, and classes are divided into orders. Orders are then divided into families, and families are divided into genera (singular: genus). Genera contain one or more species, and species may be further subdivided into subspecies or varieties.
