In practice, polygyny is far more common than polyandry. Polyandry refers to a woman who has multiple husbands.
Polygyny specifically refers to a man who has multiple wives. They can refer to women having multiple partners of any gender, men having multiple partners of any gender, or nonbinary people having partners of any gender. Polyamory and polygamy are both gender-neutral terms. Polyamory and polygamy might sound similar, but in practice, they’re quite different.