nomen

[noh-men] /ˈnoʊ mɛn/
noun, plural nomina
[nom-uh-nuh, noh-muh-] /ˈnɒm ə nə, ˈnoʊ mə-/ (Show IPA)
1.
(in ancient Rome) the second name of a citizen, indicating his gens, as “Gaius Julius Caesar.”.
Origin
1885-90; < Latin nōmen name
British Dictionary definitions for nomen

nomen

/ˈnəʊmɛn/
noun (pl) nomina (ˈnɒmɪnə)
1.
an ancient Roman's second name, designating his gens or clan See also agnomen, cognomen, praenomen
Word Origin
Latin: a name