what's a hatchback/coupe/notchback/wagon?

[kmchow]

What is the "official" definition of all these terms?? Hatchback, Notchback, wagon, coupe? WHen is a 5 door hatchback a wagon??? Are there "official" or "good" definitions???

In North America, this term is being thoroughly interchanged and mixed up. Especially with regards to 5 door hatchbacks and wagons??? Is the Mazda Protge5 a wagon or hatchback? It's sometimes being referred to as either?

http://www.mazda.ca/eng/cars/protege5/home.html
http://www.subaru.ca/interface/SubaruCA01/CarExplorerDetail02.asp?OwnerId=7500&WebPageId=3959&NewCarID=4&Range=Impreza

Shapewise, it resembles the Subaru Impreza wagon? It's been said the new MB C-Class based "coupe" is really a hatchback??
http://www.mercedes.ca/Index2.cfm?thelocation=http%3A//www.mercedes.ca/site/Home.cfm%3FPID%3D323%26NavPID1%3D136%26NavPID2%3D185%26NavPID3%3D194%26LNG%3DE

What's the definition? Hatchbacks rear tailgates do tend to slant inward and are not flat???

5 door hatchback and wagon????