cog·no·men /kɒgˈnoʊmən/

–noun, plural -no·mens, -nom·i·na  /-ˈnɒmənə/
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.” Compare agnomen ( def. 1 ).

1800–10; < L, equiv. to co– co- + nōmen name, with –g– on model of nōscī: cognōscī; see cognition

—Related forms
cog·nom·i·nal  /kɒgˈnɒmənəl, -ˈnoʊmə-/, adjective
cog·nom·i·nal·ly, adverb


Her face, while lacking neither delicacy nor classic, showed a stillness from which all frivolity was absent. Rhialto, whose expertise in the field of calligynics had earned him his cognomen, found her beautiful but severe …

Source: Tales of the Dying Earth by Jack Vance.