What's "break down" mean?

Native speaker’s answer
Rebecca
Here, to "break down" means to figuratively demolish something, such as a boundary. It can also mean to fall apart emotionally, for something like a machine to stop working, to separate something into parts, or to analyze something. Ex: Once we had broken down the concept of emotions, we could understand them better. => analyzing Ex: John broke down the door. => destroyed with force Ex: I was trying hard not to break down that day. But it was difficult. => emotionally Ex: I hope the car doesn't break down on the way to the gas station.