Family

A family was a relationship between people by genetics, marriage, adoption, or an especially strong friendship. Indeed, Sarah Jane Smith told the Tenth Doctor that he had the biggest family on Earth. (TV: Journey's End) Those in a family were typically described as relatives; those that lived prior to an individual were known as ancestors, while those that lived after an individual were known as descendants.

Raxacoricofallapatorious
Raxacoricofallapatorian families used hyphenated surnames. One family, the Slitheen, functioned as a criminal organisation in what Jocrassa Fel-Fotch Passameer-Day Slitheen refered to as a "family business". (TV: World War Three) This put them at odds with other families such as the Hostrozeen, the Blathereen, and the Hazrateen, who the Slitheen knew as cousins. (TV: Revenge of the Slitheen, AUDIO: The Taste of Death)