A “beer” is NOT just a beer.
All told, there are 27 different styles of beer, with a further breakdown of 49 substyles. Michael Jackson (the beer critic, not the singer) identifies 72 classic styles. Going further, the FDA does not allow anything to be labeled “beer” above 5.0% ABV, hence labels such as “malt liquor,” “ice,” “ale,” “porter,” “lager” on nearly all craft and higher alcohol products.
These classic definitions, however, are also rapidly evolving as modern competitions, shows and exhibitions, such as the Great American Beer Festival or the World Beer Cup, will include upwards of 80 or more styles and categories.