Thank you.

I understand unicorn to mean "a women joining a couple" and the word unicorn is referring to the fact that they are very rare and hard to find.

My friend strongly believes that unicorn is purely a single person joining a couple, doesn't need to be a women

I'm having a discussion with my friend on the definition of a "unicorn" I'm aware google says one thing, but I don't agree with google this time and I don't think the general swingers population would agree on that definition.

So...what is a Unicorn?