In biological classification, family () is
- a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the prefix sub-: subfamily (Latin: ).
- a taxonomic unit, a taxon, in that rank. In that case the plural is families (Latin )
Example: Walnuts and hickories belong to Juglandaceae, the walnut family.
What does and does not belong to each family is determined by a taxonomist. Similarly for the question if a particular family should be recognized at all. Often there is no exact agreement, with different taxonomists each taking a different position. There are no hard rules that a taxonomist needs to follow in describing or recognizing a family. Some taxa are accepted almost universally, while others are recognised only rarely.
- See also
The taxonomic term was first used by French botanist Pierre Magnol in his (1689) where he called the seventy-six groups of plants he recognised in his tables families (). The concept of rank at that time was not yet settled, and in the preface to the Magnol spoke of uniting his families into larger , which is far from how the term is used today.
Carolus Linnaeus used the word in his (1751) to denote major groups of plants: trees, herbs, ferns, palms, and so on. He used this term only in the morphological section of the book, discussing the vegetative and generative organs of plants. Subsequently, in French botanical publications, from Michel Adanson's (1763) and until the end of the 19th century, the word was used as a French equivalent of the Latin (or ). In nineteenth century works such as the of Augustin Pyramus de Candolle and the of George Bentham and Joseph Dalton Hooker this word was used for what now is given the rank of family.
In zoology, the family as a rank intermediate between order and genus was introduced by Pierre Andr Latreille in his (1796). He used families (some of them not named) in some but not in all his orders of "insects" (which then included all arthropods).
Families can be used for evolutionary, palaeontological and generic studies because they are more stable than lower taxonomic levels such as genera and species.
- Systematics, the study of the diversity of life
- Cladistics, the classification of organisms by their order of branching in an evolutionary tree
- Phylogenetics, the study of evolutionary relatedness among various groups of organisms
- Virus classification
- List of Anuran families
- List of Testudines families
- List of fish families
- List of families of spiders
- protein family
- gene family
af:Familie (biologie) als:Familie (Biologie) ar: ( ) an:Familia (bioloch a) ast:Familia (biolox a) az:F sil bn: ( ) zh-min-nan:Kho (hun-l i-ha k) ba: ( ) be: , be-x-old: ( ) bg: ( ) bs:Porodica (biologija) br:Kerentiad ca:Fam lia (biologia) cs: ele cy:Teulu (bioleg) da:Familie (biologi) de:Familie (Biologie) dsb:Sw j ba (biologija) et:Sugukond (bioloogia) el: ( ) es:Familia (biolog a) eo:Familio (biologio) eu:Familia (biologia) fa: ( ) fr:Famille (biologie) fy:Famylje ga:Fine (bitheola ocht) gl:Familia (biolox a) ko: ( ) hi: ( ) hsb:Sw jba (biologija) hr:Porodica (taksonomija) id:Familia is: tt (flokkunarfr i) it:Famiglia (tassonomia) he: ( ) jv:Kulawarga (biologi) pam:Familia (biolohia) ka: ( ) sw:Familia (biolojia) la:Familia (taxinomia) lv:Dzimta (biolo ija) lb:Famill (Biologie) lt: eima (biologija) lmo:Fam a (biolog a) hu:Csal d (rendszertan) mk: ( ) mt:Familja (bijolo ija) ms:Keluarga (biologi) nl:Familie (biologie) ja: ( ) no:Familie (biologi) nn:Biologisk familie oc:Familha (biologia) nds:Familie (Biologie) pl:Rodzina (biologia) pt:Fam lia (biologia) ro:Familie (biologie) rue: ( ) ru: sah: ( ) scn:Famigghia (biolugg a) simple:Family (biology) sk: e a (taxon mia) sl:Dru ina (biologija) sr: ( ) sh:Porodica (taksonomija) fi:Heimo (biologia) sv:Familj (biologi) tl:Pamilya (biyolohiya) ta: ( ) tt: ( ) te: ( ) tr:Familya uk: ( ) vec:Fameja (tasonom a) vi:H (sinh h c) wa:Famile (biyolodjeye) vls:Familie (biologie) zea:Femielje (biologie) zh: ( )