Fan
From polycount
A Fan is one of the ways that Triangles can be created to reuse Vertex Transforms, and thus save Memory and also Rendering time.
Once you have drawn one triangle, the next triangle only needs to load the coordinate of one additional vertex in order to draw itself, because it re-uses the vertex transforms that were already performed on its neighbor triangle. But your Engine must specifically support fans for it to work.
See also Strip.
