Definition - What does Clan mean?
A clan is a group of gamers who play as a group in multiplayer online games. The clan can be official and enabled through a function in a game's mechanics, or it may be an unofficial clan by mutual agreement. Clans may have entrance requirements that a player must meet, such as a certain level of prowess or the completion of tasks as part of an application process. In massively multiplayer online role playing games (MMORPGs) clans are referred to as guilds, but the concept is the same.
Techopedia explains Clan
Clans add an often unintentional level of immersion to online gameplay. The psychology of group dynamics works in clans just as it does in real life. This can work to keep gamers coming back to a game. If someone is slacking – that is, not gaming – they’ll hear about it from their fellow clan members. Similarly, the sense of inclusion that comes with having a clan (or guild, or gang, and so on) helps to make the virtual world even more attractive to gamers. Clans can act as a form of emergent gameplay, as the storylines and drama within a clan – played out over in-game chat – run independent of a game's central storyline.