A surname, family name, or last name is the mostly hereditary portion of one's personal name that indicates one's family. It is typically combined with a given name to form the full name of a person.
Depending on culture, the surname may be placed at either the start of a person's name, or at the end. The number of surnames given to an individual also varies: in most cases it's just one, but in many Spanish-speaking countries, two surnames are used for legal purposes. Depending on culture, not all members of a family unit are required to have identical surnames. In some countries, surnames are modified depending on gender and family membership status of a person. Compound surnames can be composed of separate names.
Using names has been documented in even the oldest historical records. Examples of surnames are documented in the 11th century by the barons in England. English surnames began as a way of identifying a certain aspect of that individual, such as by trade, father's name, location of birth, or physical features, and were not necessarily inherited. By 1400 most English families, and those from Lowland Scotland, had adopted the use of hereditary surnames.
The study of proper names (in family names, personal names, or places) is called onomastics. A one-name study is a collection of vital and other biographical data about all persons worldwide sharing a particular surname.
Surnames have not always existed and are still not universal in some cultures. The tradition has arisen separately in different cultures around the world. In Europe, the concept of surnames became popular in the Roman Empire and expanded throughout the Mediterranean and Western Europe as a result. During the Middle Ages, that practice died out as Germanic, Persian and other influences took hold. During the late Middle Ages surnames gradually re-emerged, first in the form of bynames, which typically indicated an individual's occupation or area of residence, and gradually evolving into modern surnames. In China, surnames have been the norm since at least the 2nd century BC.