In some genres, but especially in FPSs, teams of players are often called clans. Why was this specific word chosen?
This is in contrast to guild or faction in RPGs, but here I can see why - they are analogous to actual guilds or factions within the lore or setting.
Clan however doesn't make much sense to me. The word itself implies kinship, and doesn't really fit with the typical FPS themes during the rise of online gaming - mid-to-late 90's - which were mainly sci-fi or militaristic.
Was there an influential game or community that first used clan (and why), and it simply spread? Or is there some other reason why this word was chosen?