Glossary
Unicorn
In polyamorous contexts, a unicorn is a single person, often a bisexual woman, who is open to joining an existing couple as a third partner.
In polyamorous and queer dating contexts, a unicorn is a single person, most often a bisexual woman, who is open to joining an established couple to form a triad. The name reflects how rare such a person can seem to a couple searching for one. The related practice of unicorn hunting, usually a couple seeking a third who will date both of them but no one else and follow rules the couple set in advance, draws frequent criticism. The concern is that it can treat the third person as an interchangeable addition rather than someone forming two genuine new relationships with equal standing. Community writing has since pushed toward more ethical, consent-centered approaches to non-monogamy.
Learn more: en.wikipedia.org/wiki/Unicorn_hunting