Pronunciation: (kog-nō'mun),[key] —n., —pl.-no•mens, -nom•i•naPronunciation: (-nom'u-nu).[key] 1. a surname.
2. any name, esp. a nickname.
3. the third and commonly the last name of a citizen of ancient Rome, indicating the person's house or family, as “Caesar” in “Gaius Julius Caesar.” Cf. agnomen (def. 1).