Polygamy

ポリガミー

porigamī

(the having of a plurality of socially bonded sexual partners at the same time — see also polygyny, polyandry)

多婚性

takonsei

(zoology: the state or habit of having more than one mate)

複婚

fukukon

(the having of a plurality of socially bonded sexual partners at the same time — see also polygyny, polyandry)