Kin Groups and Descent. Some patrilineages have permanent family names that indicate ramification. For instance, one family of Kohanim (families descended from the Aaronide priests) is called "Dwek HaKohen." One branch of the Dwek may be the Dwek Halusis, while another may be the Dwek Kassab. These are not corporate groups, however, with fixed membership and estates.
Kinship Terminology. Like other speakers of Arabic, these Jews use the bifurcate-collateral system of differentiating siblings of the father from siblings of the mother and the Sudanese terminology of designating the father's brother's son as ibn ʿamm, the father's brother's daughter as bint ʿamm, the mother's brother's son as ibn khal , the father's sister's daughter as bint ʿammti, the mother's sister's son as ibn khalti, and so on.