Unicorn

Unicorn is community shorthand for a bisexual or queer woman who dates established heterosexual couples as a third. The metaphor is of a rare and prized creature — and the term carries different valences depending on who is using it and how.

Used pejoratively (most commonly), unicorn names the role that established couples cast outside women in when they go looking for a recruited third. The unicorn in this framing is a person whose function in the couple's structure is predefined — date both equally, do not develop asymmetric feelings, accept being secondary, do not threaten the primary couple — terms the unicorn did not write and that exist to protect the couple. This pattern is criticised heavily in established polyamorous communities; see the entry for unicorn-hunting for the structural critique.

Used neutrally, unicorn is sometimes a self-description by bisexual women who do enjoy dating couples and find healthy ways to do it. The pattern can work when the unicorn enters as a fully empowered individual with veto-equivalent agency, when the couple has done their work and is not approaching the third as a couple-shaped applicant, and when the relationship is allowed to grow into whatever shape it grows into rather than being constrained by predetermined rules.

The label is gendered (men are not typically called unicorns even when they fulfil the structurally-analogous role; the term 'dragon' is occasionally used) and is increasingly contested. Many bisexual women who date couples reject the term as flattening their experience into a couple-centric role; others use it ironically; others use it sincerely. As with most community vocabulary, the right approach is to follow the lead of the person being described.