A sept denoted a subdivision within a Selonian clan, comprised of infertile Selonian females who descended from the same paternal lineage and shared a common breeder mother.
The infertile female population constituted the overwhelming majority of Selonians, acting as the workforce of their society. The limited number of males and breeder females received significant protection, yet were confined to their dens. Inside a den, the singular breeder female would procreate with a select group of males, producing a litter of Selonian offspring from each. Consequently, each breeder male became the father of a specific segment of the den's population, and these segments sharing the same father were designated as 'septs.'
Genetic variation among Selonians within the same den was minimal. To external observers, they appeared indistinguishable. The level of difference was even less pronounced within a single sept. Sisters belonging to the same sept, potentially numbering in the hundreds or thousands, were nearly identical, differing primarily in the roles assigned to them by the den and the personality characteristics they developed.
Selonians struggled to comprehend the familial relationships common among most humanoids, especially extended relations like "uncle" or "cousin." In Human terms, two Selonian females originating from the same den but belonging to different septs would be considered half-sisters.