Triad

A triad is a polycule shape in which all three people are partnered with each other. Where a V has two of the three possible edges, a triad has all three: A is partnered with B, B is partnered with C, A is partnered with C. The shape draws as a closed triangle.

Triads form in two distinct ways, with quite different dynamics. The first is the organic triad: three people who were already partnered in some pairings discover that the third edge develops, often slowly. The second is the recruited triad: an established couple deliberately seeks a third to form a triangle, often with an asymmetric expectation that the third's experience will somehow mirror the couple's. The first pattern produces stable triads more often than the second; the second is closely related to the unicorn-hunting failure mode.

What is hard about triads is that they ask three relationships to be simultaneously alive — A-B, B-C, A-C — and to be roughly in balance, even though they will inevitably vary in intensity, pace, and quality. The first triads people form often founder when one edge weakens and the structure cannot absorb the asymmetry. Stable triads usually have spent years navigating those imbalances explicitly.

Throuple is an informal synonym that has gained traction in mainstream coverage. Practitioners use it with varying degrees of comfort; triad is the more established term in the polyamory community.