Does that make my Civic coupe a sedan? Or is it a two door sedan as opposed to a four door sedan? Maybe the confusion is popular or common terms versus technical terms. Ask a botanist what a tomato is, and they'll tell you it's a fruit. But that isn't particularly useful when making a fruit pie. Maybe it depends on the audience. Talking to a group of vehicle designers? Referring to a Mustang's structure as being a sedan could make sense. But if I were to list my Civic on Craigslist as a sedan, every single response would call me a liar. That might explain my annoyance with the author. Nobody likes the guy at a party who declares a tomato a fruit. I don't think he knows his audience, or he's deliberately being obtuse to try to feel smarter than them.