a sexual relationship involving three persons, two of whom never have sex with EACH OTHER. For example, in a heterosexual triangle M-F-M, the two men have sex with the woman but never with the other.

See closed triangle.
A famous example of an open triangle was that involving Manuel de Godoy, Queen Maria Louisa, and King Carlos IV . In exchange for servicing two of the most repulsive people in Europe, Godoy made an enormous fortune and became the effective ruler of Spain.

The relationship was an open triangle because the king and queen found each other unbearable.
by Abu Yahya March 21, 2010
Get the open triangle mug.
On Snapchat when someone opens your snap and doesn't reply. An open triangle appears next to their name and you are filled with a feeling of rejection.
"Man I never snap Landon anymore, he always open triangles me."
by XxOMGxX May 26, 2015
Get the Open Triangle mug.
When you ignore another person's snap.
Dude this kid keeps on sending me stupid snaps I got no choice but to open-triangle
by fivesome August 14, 2016
Get the Open-triangle mug.