Final answer:
The larger category encompassing both polygyny and polyandry is polygamy. Both are forms of marriage where one individual has multiple spouses, distinguished by the gender of the singular spouse with multiple partners.
Step-by-step explanation:
The larger category that includes both polygyny and polyandry is polygamy. Polygamy is a type of marriage where one individual is married to more than one spouse simultaneously. While polygyny refers to a man being married to multiple women, polyandry involves one woman being married to multiple men. Though these practices differ, they both fall under the broader category of polygamy, which is accepted in a majority of cultures worldwide. Polygamy can serve to expand a family's labor force, create wide kinship networks, and increase social status or political alliances. Yet, it is important to note that cultural, economic, and social variables heavily influence these marital structures.