clan is a group of people linked by kinship, which is defined by the existence of a common ancestor. Clan means children in Scottish Gaelic, also called clannad, which means family.
The clan does not need to be blood relatives, specifically, the main value is having symbolic ties. The clans function as a kind of tribe, and usually have more than 7000 people as members. Some clans may be made up of only men, others only women, and others irrespective of gender.
Clans are called patrilineal, matrilineal and bilateral. Patrilineal is when members are only men, matrilineal is when they are only women, and bilateral depends on kinship rules and norms.
Clans generally constitute a specific tribe within a larger place, such as a large city. There are the Chinese clans, in New York, for example, the Japanese, Scots, Irish, etc. But the opposite can also happen, the clan being larger than the population of a city, which happens in some Arab cities.