matronymic

A matronymic is a personal name based on the name of one's mother, grandmother, or any female ancestor. It is the female equivalent of a patronymic. In most societies, matronymic surnames are far less common than patronyms. In the past, matronymic last names were often given to children of unwed mothers. Other times when a woman was especially well known or powerful, her descendants would adopt a matronym based on her name.