/bɪˈɡæməs ˈjuːnjən/ – Phrase
Definition: chế độ trùng hôn, việc lấy hai vợ, việc lấy hai chồng.
A more thorough explanation: A bigamous union refers to a marriage in which one or both parties are already legally married to another person. This act of entering into a second marriage while still being legally married to someone else is considered illegal and void in most jurisdictions.
Example: The court found that John was guilty of entering into a bigamous union with another woman while still legally married to his first wife.