Before revision: Matrilateral cross-cousin marriage (mother's brother's daughter marriage) is typically used by anthropologists to describe a form of marriage in which sons of one consanguineal group marry the daughters of the consanguineal group from which their mother originates.
After revision: Matrilateral cross-cousin marriage (mother's brother's daughter marriage) is typically used by anthropologists to describe a form of marriage in which sons of one kin group marry the daughters of the kinthe group from which their mother originates.