What is the meaning of the "M" in BMW M series?

[AlinaFitz]

BMW M series "M" means the following: 1. The M series is a department of BMW (M Department), which is BMW's original high-performance department. It specializes in modifying BMW sedans, using the standardized BMW 3 Series, 5 Series, and 6 Series as blueprints to create ultra-high-performance models. The prices are very high, and BMW M GmbH is a specialized organization within the BMW Group, whose mission is to push the performance of BMW cars to the peak; 2. Unlike AMG and ABT, the M high-performance department is an in-house organization of BMW, not a cooperative entity, and has access to much better technical support;