How does polygyny differ from polyandry?

Polygyny and polyandry are both forms of polygamy, but they differ fundamentally in the gender of the spouses involved.12

• Polygyny: This is a marriage in which a man is married to two or more women simultaneously. It is the most common form of polygamy. In many cultures, it is practiced as sororal polygyny, where the cowives are sisters, a structure often preferred for the mutual support it provides.123
• Polyandry: This refers to a marriage in which a woman is married to two or more men at the same time. It is a comparatively rare phenomenon, often emerging as a response to specific local conditions such as sex ratios, male mortality, or economic factors. When the husbands are brothers, the practice is known as adelphic or fraternal polyandry.142

While both patterns involve plural spouses, they are distinct from group marriage, which involves multiple men and multiple women in a single union.2