What refers to the feminine form of a father's nomen or ordinal position among siblings?

The term that refers to the feminine form of a father's nomen, or the ordinal position among siblings, is correctly identified as "patronymic." In Roman naming conventions, a patronymic is derived from the father's name and frequently indicates lineage. While "nomen" is a key part of Roman names, specifically the second name used to denote the gens (clan or family), it does not specifically capture the feminine aspect nor the ordinal relationship among siblings. "Cognomen" refers to additional names that can provide further distinction within the family but does not address the aspect of feminine form. "Women’s names" is a broad category and does not specifically relate to the concept of lineage or familial ordering in the context of Roman naming conventions. The concept of a patronymic is therefore most closely aligned with the feminine form of a father's nomen, as it signifies both lineage and connection to familial identity.