Byname and Last name

Byname noun - A descriptive or familiar name given instead of or in addition to the one belonging to an individual.

Last name and byname are semantically related in surname topic. In some cases you can use "Last name" instead a noun "Byname".

Last name noun - A name shared by members of a family.

Byname and last name are semantically related in family name topic. You can use "Byname" instead a noun phrase "Last name".