The term breakdown can refer to a variety of situations, but generally it means a failure or stopping of something. It could be used in reference to an engine breaking down while driving, indicating that the car has stopped working and is no longer operational. In a broader sense, it may also describe a situation where emotions become overwhelming leading to a mental breakdown. Additionally, the term can refer to a detailed analysis of something, such as a marketing breakdown which would be an in-depth examination of how a particular product or service is being marketed and sold.