n. Three people in a romantic relationship.
Also Seen As
In that case, every argument for recognizing two men's bond as marital — equality, destigmatization, extending economic benefits — would also apply to recognizing romantic triads ("throuples," as they are now known).
—Robert P. George, “Gay marriage, then group marriage?,”, March 21, 2013
"Tim is wide open to defining who he is sexually," says James. "The setup is that Tammy’s and my character consider a relationship with Sean. We’re calling it a throuple." ("Threelationship" also works.)
—James Dziemianowicz, “D'Arcy James scores a 'Big C' triple play,” New York Daily News, May 12, 2012
2004 (earliest)
It's the hottest thing in romantic commitment since monogrammed towels. It's set Provincetown abuzz. And now it's got a catchy name: "throuple," as in couple, only consisting of three (usually same-sex) members instead of two.
—Edith Zimmerman, “City Journal,” Boston Magazine, October 01, 2004
A less popular but more euphonius synonym is threelationship, which first appeared in a December 12, 2007 Urban Dictionary post.