Aimak

The Aimak (or Eimak) are nomadic or semi-nomadic tribes of Mongolian stock inhabiting the north and north-west Afghan highlands immediately to the north of Herat. They were originally known as chahar (the four) Eimaks, because there were four principal tribes: the Taimani[?] (the predominating element in the population of Ghur[?]), the Ferozkhoi[?], the Jamshidi[?] and, according to some authorities, the Hazara. The Aimak peoples number upwards of a quarter of a million, and speak a dialect said to be closely related to the Kalmuck[?]. They are Sunnite Muslims in distinction from the Hazara who are Shiites. They are predominantly of Iranian or quasi-Iranian blood, while the Hazara are Turanian[?]. They are a bold, wild people and renowned fighters.

The name is Mongolian for clan, or section of a tribe.

(from an old encyclopedia)