In Wosterhiem, particularly among human and dwarvish nations on the mainland, surnames are an important thing. It is quite common, in fact, for a person to have two surnames, one for family, one for house. Exceptions to this generally fall into two categories, Housekeep families who rule a house, and houseless folk; who are either wanderers from afar or are the very poor and discarded folk.
If you were to enter a town in say, Bulvirk, and somebody asked for your name and you would say 'God'Phrey of Ellis'. God would be assumed to be your first name,(although with that name an eyebrow would be raised) Phrey would be the name of your family, and Ellis would be the name of your house.
Houses are a big deal. Families band together under the housekeep family, which is tasked with handling the official business of a house, its land and its defences. They aren't overlords, however, and if the member families of a house find that they do not like how things are going in the household, they may leave with their possessions or call a moot, where a majority vote can topple the ruling family and instate a new family as housekeep. The family name becomes the house name, and people are encouraged to get with it or get out.
Members of the housekeep family have the option of adding term 'son of' or 'daughter of' before their family name or use the the suffix -son as a contraction. The head of the housekeep family, and by proxy, head of the household, would use the housekeep family name as would his or her spouse. An example: "My name is Tim Sprekson, child of Sonja Sprek. I'm here to buy lumber on her behalf."
Familial names are passed down haphazardly, based on the conventions of their parents union. A son who falls for a girl in a neighboring house and relocates to live with her is expected to change his house name to hers, but may opt to keep his familial surname. Their children will likely be given her familial surname, unless he is a man of renowned bravery and she accepts his desire to form a lineage.
Lineages are valuable. If you have an ancestor that is known for some great deed or accomplishment, it goes a long way towards boosting one's social and political standing. Many a house is built around a lineage.