Well, if you mean to others, I don't explain it to anyone. No one would get it. To say that it is about fear of rejection/abandonment, or emotional dysregulation wouldn't help because most people have a "Well, just stop being that way" reaction. To the few who know I'm in therapy, I tell them it is for depression.

To myself, BPD is good as an explanation, as is the sticky at the top of the forum. The diagnosis helped me a lot to understand that I am truly different from some others, like in the intense emotions and all that comes with that. Others feel the same emotions and can cope with them, but with me it's debilitating or I need to act on them, usually some form of running.
There's just so much to BPD.