Meaning

noun 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)

adjective of or derived from a personal or family name

originFrom Ancient Greek πατήρ (patḗr, “father”) + ὄνυμα (ónuma, “name”) (a variant form of ὄνομα (ónoma, “name”)). Also patronym + -ic, from patro- + -onym.

Etymology from Wiktionary, CC BY-SA 3.0