The Collaborative International Dictionary
To-name
To-name \To"-name`\ (t[=oo]"n[=a]m`), n. [prep. to + name.]
A name added, for the sake of distinction, to one's surname,
or used instead of it. [Scot.]
--Jamieson.
Wiktionary
to-name
n. 1 A name added to another name; surname. 2 A name in addition to the Christian name and surname of an individual, to distinguish him or her from others of the same name and usually indicating descent, place of residence, or some personal quality or attribute. Such to-names are often employed where the same families continually intermarry, and where consequently the same name is common to many individuals.