The practice of a woman having several husbands is known as:
1. Endogamy
2. Exogamy
3. Polygyny
4. Polyandry

4

Polygyny is the practice of a man having several wives.
Endogamy refers to marriage within a unit- this could be a kin group, caste, or a group living in the same locality.
Polyandry is the practice of a woman having several husbands.
Exogamy refers to marriage outside the unit.