Describes a four person polyamorous relationship.
Due to the nature of how a quad is formed, each member does not necessarily have romantic or sexual involvement with every other member. Quads often form when two polyamorous couples take an interest in one another.
Members of quad relationships are often confused as swingers because they appear to be in a committed relationship, but are often seen with other people. It differs from swinging in the sense that the four members of the quad are committed to the relationship.
When Mike and Stacey first met Jim and Annette, they immediately felt a strong sense of attraction. After Mike and Stacey found out that their new friends were polyamorous they decided to approach Jim and Annette with the idea of forming a quad.