familias

Familias is the plural form of familia in Spanish and Portuguese, used to denote families or kin groups, within households or extended lineages. In everyday language, it refers to social units defined by blood, marriage, or adoption.

In biology, the term family (plural families) is a formal taxonomic rank between order and genus. Family names in zoology end with -idae and in botany end with -aceae. A family groups one or more genera that share broad similarities and a common evolutionary ancestry. Examples include Hominidae (great apes) and Felidae (cats) in animals, and Rosaceae (roses) and Asteraceae (daisy family) in plants. Classification at the family level can change with new phylogenetic evidence.

Historical context: The rank was incorporated into the Linnaean system in the 18th century and has since been standardized by the codes of nomenclature in zoology and botany. The term "familias" itself in English is not used as a formal taxonomic label; the plural is "families"; "familias" appears in Spanish and Portuguese texts to mean families.

In non-scientific usage, "familias" can refer to social groups or households within a culture, and may be a key concept in studies of kinship, family structures, and demography.