A family group is a social unit consisting of people related by blood, marriage, or adoption. The term 'family group' can refer to a variety of different types of groups, including clans, tribes, genera, mafias, and septs. A CLAN is a group of people united by actual or perceived kinship and descent, while a TRIBE is a social division in a traditional society consisting of families linked by social, economic, religious, or blood ties. A GENUS is a taxonomic rank used in the biological classification of living and fossil organisms, while a MAFIA is an organized crime syndicate originating in Italy. Finally, a SEPT is a division of a family, especially of a Scottish or Irish CLAN.