Family (n.): Family is a taxonomic rank between order and genus. Taxonomy is the classification of living organisms into groups. All classified animals and plants belong to a family. The order of taxonomic ranks are as follows: Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species. The variety of certain plants is often indicated in single quotes (Crassula 'Morgan's Beauty,' for example) and is not part of the plant's official classification.