patronymic

American Heritage® Dictionary of the English Language, Fourth Edition

1. adj. Of, relating to, or derived from the name of one's father or a paternal ancestor.
2. n. A name so derived.

Century Dictionary and Cyclopedia

1. Derived from or constituting the name of a father or ancestor.
2. n. A name derived from that of parents or ancestors: as, Tydides, the son of Tydeus; Pelides, the son of Peleus; Fitzwilliam, the son of William; Williamson, the son of William; Pavlovitch, the son of Paul; Macdonald, the son of Donald; in general use, a, family name; a surname. The usual Anglo-Saxon patronymic ending was -ing (see -ing).
3. In anthropology, relating to that form of society in which the child takes its name from the father's family, or in which the child is reckoned as a member of the paternal family.

Wiktionary

1. adj. Derived from ancestors; as, a patronymic denomination.
2. n. name acquired from one's father's, grandfather's or earlier male ancestor's first name. Some cultures use a patronymic where other cultures use a surname or family name; other cultures (like Russia) use both a patronymic and a surname.

GNU Webster's 1913

1. adj. Derived from ancestors.
2. n. A modification of the father's name borne by the son; a name derived from that of a parent or ancestor; ; also, the surname of a family; the family name.

WordNet 3.0

1. adj. of or derived from a personal or family name
2. n. a family name derived from name of your father or a paternal ancestor (especially with an affix (such as -son in English or O'- in Irish) added to the name of your father or a paternal ancestor)