“[Agnati were] all individuals subject for the time being to the same patria potestas, or who would be so subject were the common ancestor alive. Brothers and sisters, with their uncles, aunts, nephews, nieces, and other colla-terals (not having been received into another family), if related through males, were agnates. The civil issue of the state was the Agnatic Family. Cognates were all persons who could trace their blood to a single ancestor or an-cestress, and agnates were those cognates who traced their connection exclusively through males.” John Bouvier, Bouvier’s Law Dictionary (8th ed. 1914).
agnatus
agnatus (ag-nay-t[schwa]s), n. [Latin] Roman law. A person related through the male line. Cf. COGNATUS.