Forbidden to you for marriage are: your mothers, your daughters, your sisters, your paternal aunts, your maternal aunts, daughters of your brothers, daughters of your sisters, your foster-mothers, your foster-sisters, the mothers of your wives, your stepdaughters under your guardianship from those wives with whom you have consummated your marriage, but there is no blame on you in marrying your stepdaughters if you have not consummated your marriage with their mothers, whom you have divorced, and the wives of your own real sons; and you are also forbidden to take in marriage two sisters at one and the same time except what happened prior to this commandment; surely Allah is Forgiving, Merciful.
Meaning:-
Forbidden: not allowed; banned.
Foster-mother: a woman who takes the place of a mother in raising a child.
Foster-sister: a girl brought up with another child of different parents.
Consummate:make (a marriage or relationship) complete by having sexual intercourse.