ETYM Old Eng. ekename surname, hence, a nickname, an ekename being understood as a nekename, influenced also by Eng. nick, v. Related to Eke, and Name.
A familiar name (often a shortened version of a person's given name); SYN. moniker, cognomen, sobriquet, soubriquet.

ETYM Pref. sur + name; really a substitution for Old Eng. sournoun, from French surnom. Related to Sur-, and Noun, Name.
The name used to identify the members of a family (as distinguished from each member's given name); SYN. family name, cognomen, last name.