What you might be thinking of is an "N". For instance, my subject line has four people in it (not counting Bee). I talk sometimes about the vee of me, Gia, and Eric, but technically if you look at the entire set of relationships I'm part on an N... it's a V with an extra line coming off of one of the "wings", see? That extra line would represent my relationship with Davis. If you were to start at one end and trace the shape of the letter, the four points would represent in order Davis, me, Gia, and Eric. If Eric started dating someone it'd be an "M", I suppose, and after that it would just become a squiggle.
But really, the easier way to think about it is at the level of vees. Me, Gia, and Eric are one vee, and Davis, me, and Gia are another. In the former I'm on a wing, in the latter I'm the hinge. I have an easier time thinking of the former as a vee because we're all really close and could probably have a triad if Eric were up for it and I find the term vee captures that dynamic well. It's important to be able to explain it in a way people get, because from the outside we can look very much like a triad and that misconception can be frustrating because Eric and I are not, in fact, romantically involved. The latter I usually don't think of as a vee, even though it technically is, because Davis and Gia don't know each other well and seldom interact at this point, so thinking of the three of us as part of one relationship structure seems a little odd.
I have no idea if that all made sense or not.