Both of these are beer. Lager refers to beer that is fermented using yeast that ferments on the bottom of the fermentation vessel. Lager is relatively new on the brewing scene, as it was not feasible to make in many climates before refrigeration. Some local examples of lager are Tiger and Tiger Classic, Anchor, and Carlsberg. Ale, on the other hand, is made with yeast that ferments on the top of the beer, floating around and making a nice fuzzy white pile.
Ale yeast prefers warmer temperatures, and ferments more quickly than does lager yeast.
The resulting beer is generally more flavorful and darker in color than is most lager beer. It is generally less carbonated than is lager, but this is due more to the way it is conditioned and handled than to the yeast itself. It is an ale, and ale is beer, so stout is beer. Belgium also makes some damn fine ales. One of the more unusual ales made in Belgium is known as lambic .