There are two major forms of beer: Lager and Ale.
Ale uses a top-fermenting barley yeast and is subdivided into Pale, Brown, Stout&Porter, Belgian, German and Cream Ales.
Lager. meanwhile,has been brewed in Germany for over 500 years. It is stored for several weeks before serving and uses lighter malts.
There are countless brands of each, but if you want to know whether a specific drink is lager or beer, just ask.