Agnatic is a family relationship or kinship in which people only trace their ancestry and relationship pattern through their fathers or the male line.
The adjectival form of agnate is called agnatic and is often used as a synonym for patrilineal. Roman law defined agnates as those who had a common male ancestor. They are the people who are exclusively linked to one another via men in current terminology. Therefore, agnate ancestry is the same as patrilineal descent. It is a critical subject in the sociological and anthropological study of society.