"Unibody" essentially means the vehicle chassis is constructed by integrating the body and frame as one piece, instead of having a body with separate frame. Here, folks are discussing a major structural component of the unitized body. Do some extracurricular reading about unibody (a.k.a. monocoque, or semi-monocoque) construction.A lot of people writing about frames on this thread. Is not the Acadia a UniBody construction vs frame construction?