A couch and sofa are similar but not the same, a sofa is a fancier couch, usually seats three to four, depending on the humans. A settee is much fancier, usually lower arms, not nearly as comfy to sit on, and more wood or metal than fabric or leather. A chaise lounge has no arms or very short ones with a long seat and a curved back. I have a settee in my library, a sofa and a couch in the living room, and a chaise lounge in the mudroom.