一夫多妻 (いっぷたさい) Japanese meaning | KotomoraMeanings
1
noun, noun which may take the genitive case particle 'no'
polygamy; polygyny
yojijukugo (four-character idiom)
Specifically refers to one husband having multiple wives. The broader term for multiple spouses is 複婚 (ふくこん).
In a polygynous society, a man is allowed to have multiple wives.