baseball card dimensions

[darwinbulldog]

Does your definition of a baseball card include a minimum or maximum height, width, or thickness? Do the surfaces have to be rectangular? I personally would be okay considering a disk of 1 mm² or 10 ft² a baseball card as long as it met the other criteria, but I feel like a baseball card does at least have to be a card. That said, I do actually collect 1946-47 Propaganda Montiels, which look a heckuva lot like baseball cards, but once you've held one you know they aren't actually cards at all, since they're only about as thick as a Bible page.