Which term refers to the practice of having multiple spouses simultaneously?

Polygamy is the term that describes the practice of having multiple spouses at the same time. This marital arrangement can take two forms: polygyny, where one man is married to multiple women, and polyandry, where one woman is married to multiple men. Polygamy is often associated with specific cultural, social, or religious practices, and it contrasts sharply with monogamy, which involves a one-to-one marriage structure.

Monogamy, as indicated, refers to having one spouse at a time, which does not align with the idea of multiple spouses. Serial monogamy describes a situation where an individual has multiple spouses, but only one at a time, typically through a sequence of marriages or relationships, which again does not fit the definition of polygamy. Endogamy refers to marrying within a specific social group or community, and it does not pertain to the number of spouses someone may have. Understanding these definitions clarifies why polygamy is the correct term for the situation described in the question.