Polyandry, form of marriage in which a woman has more than one husband or mate at the same time. Two principal forms of polyandry exist today. Among the Nair people, who inhabit India's Malabar Coast, a woman may marry several men of equal or superior rank. In areas of Tibet, a woman may marry the eldest brother of a family and then also take his brothers as mates. In most countries, polyandry is illegal.
taken from Encarata encyclopedia