polygyny

noun3

1. •
   The condition of an ant colony that has multiple egg-laying queens.
2. •
   The state or practice of a man having more than one wife at a time; plurality of wives; marriage between one man and multiple wives.

   • We may infer that in most cases where polygyny exists, monogamy co-exists to a greater extent, and in all other cases to a considerable extent. — 1883
3. •
   Synonym of polygamy.