A more thorough explanation:

Potestas is a Latin word that means "power." In Roman law, it referred to the authority or power held by a magistrate to enforce the law or the authority of an owner over a slave. It also referred to the power held by the male head of a family over his legitimate and adopted children, as well as further descendants in the male line, unless emancipated. This power was called patria potestas, which means "paternal power." For example, in ancient Rome, a father had extensive powers over his family, including the power of life and death. He could inflict any punishment, however severe, on his children. He could also sell them for a slave or put them to death, even after they had risen to the highest honors in the state. This shows how the patria potestas had a despotic character and was gradually becoming more in the nature of a responsibility to support and maintain family members. Over time, the broad nature of the patria potestas gradually became more in the nature of a responsibility to support and maintain family members. But except in early Roman history, a wife did not fall into her husband's power but remained in her father's until she became sui juris by his death. This shows how the patria potestas was an institution that was decaying by the end of the Republic. In summary, potestas is a Latin word that means "power" and refers to the authority or power held by a magistrate to enforce the law or the authority of an owner over a slave. It also refers to the power held by the male head of a family over his legitimate and adopted children, as well as further descendants in the male line, unless emancipated.