A name used instead of or in addition to a person's ordinary given name and surname; a byname.
Origin
Mid 17th century; earliest use found in Thomas Urquhart (1611–1660), author and translator. From classical Latin ag-, variant of ad-ad- + name, after classical Latin agnōmenagnomen.
agname2
/ˈaɡneɪm/
verb
[with object]With double object, in pass. To be styled or called instead of or in addition to an ordinary given name and surname.
Origin
Mid 17th century; earliest use found in Thomas Urquhart (1611–1660), author and translator. From agname.