Surname in the context of "Cognomen"

A legal name or wallet name is the name that identifies a person for legal, administrative and other official purposes. A person's legal birth name generally is the name of the person that was given for the purpose of registration of the birth and which then appears on a birth certificate (see birth name), but may change subsequently. Most jurisdictions require the use of a legal name for all legal and administrative purposes, and some jurisdictions permit or require a name change to be recorded at marriage. The legal name may need to be used on various government issued documents (e.g., a court order). The term is also used when an individual changes their name, typically after reaching a certain legal age (usually eighteen or over, though it can be as low as fourteen in several European nations). A person's legal name typically is the same as their personal name, comprising a given name and a surname. The order varies according to culture and country. There are also country-by-country differences on changes of legal names by marriage. (See married name.) Most countries require by law the registration of a name for newborn children, and some can refuse registration of "undesirable" names.

The birth name is the name of the person given upon their birth. The term may be applied to the surname, the given name or to the entire name. Where births are required to be officially registered, the entire name entered onto a births register or birth certificate may by that fact alone become the person's legal name.

Arbitrariness is the quality of being "determined by chance, whim, or impulse, and not by necessity, reason, or principle". It is also used to refer to a choice made without any specific criterion or restraint.

Arbitrary decisions are not necessarily the same as random decisions. For example, during the 1973 oil crisis, Americans were allowed to purchase gasoline only on odd-numbered days if their license plate was odd, and on even-numbered days if their license plate was even. The system was well-defined and not random in its restrictions; however, since license plate numbers are completely unrelated to a person's fitness to purchase gasoline, it was still an arbitrary division of people. Similarly, schoolchildren are often organized by their surname in alphabetical order, a non-random yet an arbitrary method—at least in cases where surnames are irrelevant.

Over the course of some fourteen centuries, the Romans and other peoples of Italy employed a system of nomenclature that differed from that used by other cultures of Europe and the Mediterranean Sea, consisting of a combination of personal and family names. Although conventionally referred to as the tria nomina, the combination of praenomen, nomen, and cognomen that have come to be regarded as the basic elements of the Roman name in fact represent a continuous process of development, from at least the seventh century BC to the end of the seventh century AD. The names that developed as part of this system became a defining characteristic of Roman civilization, and although the system itself vanished during the Early Middle Ages, the names themselves exerted a profound influence on the development of European naming practices, and many continue to survive in modern languages.

A personal name, full name or prosoponym (from Ancient Greek prósōpon – person, and onoma –name) is the set of names by which an individual person or animal is known. When taken together as a phrase, they all relate to that one individual. In many cultures, the term is synonymous with the birth name or legal name of the individual. In linguistic classification, personal names are studied within a specific onomastic discipline, called anthroponymy.

In Western culture, nearly all individuals possess at least one given name (also known as a first name, forename, or Christian name), together with a surname (also known as a last name or family name). In the name "James Smith", for example, James is the first name and Smith is the surname. Surnames in the West generally indicate that the individual belongs to a family, a tribe, or a clan, although the exact relationships vary: they may be given at birth, taken upon adoption, changed upon marriage, and so on. Where there are two or more given names, typically only one (in English-speaking cultures usually the first) is used in normal speech.

A given name (also known as a forename or first name) is the part of a personal name that identifies a person, potentially with a middle name as well, and differentiates that person from the other members of a group (typically a family or clan) who have a common surname. The term given name refers to a name usually bestowed at or close to the time of birth, usually by the parents of the newborn. A Christian name is the first name which is given at baptism, in Christian custom.

In informal situations, given names are often used in a familiar and friendly manner. In more formal situations, a person's surname is more commonly used. In Western culture, the idioms "on a first-name basis" and "being on first-name terms" refer to the familiarity inherent in addressing someone by their given name.

When a person (traditionally the wife in many cultures) assumes the family name of their spouse, in some countries and cultures that name replaces the person's previous surname, which in the case of the wife is called the maiden name ("birth name" is also used as a gender-neutral or masculine substitute for maiden name), whereas a married name is a family name or surname adopted upon marriage.

In some jurisdictions, changing names requires a legal process. When people marry or divorce, the legal aspects of changing names may be simplified or included, so that the new name is established as part of the legal process of marrying or divorcing. Traditionally, in the Anglophone West, women are far more likely to change their surnames upon marriage than men, but in some instances men may change their last names upon marriage as well, including same-sex couples.