Actually, it's Beamer, not Beemer, which refers to the motorcycle, and Bimmer refers to the car. Technically, that is. But a lot of people just call them Beamers, whatever they are. Some car owners may get offended, but for the most part it's the motorcycle owners who get pissed when you call their bikes Bimmers. Unless I'm on the forums, I simply call mine a BMW.
All this confusion over a company that originally made airplane engines and train brakes