What do the letters mean on a BMW?

The letters on a BMW typically represent the model series and engine type. For example, in the BMW 3 Series, the "3" indicates the series number, while additional letters like "i" or "d" signify the engine type, with "i" indicating a gasoline engine and "d" indicating a diesel engine. Other suffixes, such as "x," denote all-wheel drive. Overall, the designation helps identify the vehicle's size, performance, and fuel type.