"Art Deco" or "Advance Design". Usually, when you see it here like that, it's the latter.
They're marketing descriptions for those particular body styles. Some have been assigned by GM, and some have been acquired elsewhere.
"Advance Design" covers any Chevy truck made from 1947 Second Series - 1955 First Series. The name comes directly from GM's Marketing Department.
"Art Deco" covers any civilian-made chevy truck made from 1941 Model Year - 1947 First Series. I've also seen them called "Wurlitzer" trucks (because of all of the chrome). Interestingly enough, the Art Decos were, as far as I know, called "Victory" Series trucks by GM.
