Ethnonymic surname
Ethnonymic surnames are surnames or bynames that originate from ethnonyms. They may originate from nicknames based on the descent of a person from a given ethnic group. Other reasons could be that a person came to a particular place from the area with different ethnic prevalence, from owing a property in such area, or had a considerable contact with persons or area of other ethnicity. Also, they may reflect the fact that a given person matched a particular ethnic stereotype.
In some research ethnonymic surnames are grouped together with toponymic surnames into "surname by origin", because many ethnonyms may be viewed as demonyms as well; e.g., Litwin is either a person of Lithuanian ethnicity or one from Grand Duchy of Lithuania.
Etnnonymic surnames/nicknames may give rise to patronymic surnames: Arnaudov (from Arnaut, i. e. Albanian), Crnogorčević (from Crnogorac, Montenegrin), Horvatović (from Croat), Grković (from Greek).