Metamour
A metamour is your partner's other partner — someone connected to you through a shared partner rather than by a direct relationship.
A metamour is the partner of your partner: someone you are linked to indirectly through the person you share, without necessarily having a romantic or sexual relationship with them yourself. The word combines the Greek "meta" (beyond) with "amour" (love).
Metamour relationships range widely. In kitchen-table polyamory they may be close friends who share meals and holidays; in parallel polyamory they may rarely meet at all. Either way, treating a metamour with respect is central to a healthy network.
Many people find that a good relationship with a metamour eases jealousy and builds trust across the whole network. Even where there is no friendship, basic courtesy and clear boundaries keep everyone comfortable.
Frequently asked
No. Some are close, others barely interact. What matters is mutual respect and clear boundaries.
From the Greek meta, meaning beyond, and amour, meaning love — literally the love beyond your own relationship.