How to coin a term.

I was given a challenge beyond anything I ever emagined doing. I'm supposed to coine a term and/or phrase for the ethnic German cleansing that took place after the second world war. This terma will be used in every artical, story, book, movie and dinner table conversation had about the topic. It must be something that will make everyone think of one thing and one thing only, the ethnic German cleansing.

How did a girl who grew up in the mid-west get an opportunity to do something that people never think of doing? How does one coin a term? I started by looking on ask.com then I went to google and now I'm writing in my blog trying to figure out my next step. It's not clear cut at all. I must come up with something that will make sense in every language and mean the same thing. That's the trick, how to find a word that means the same thing in every language. From what I know about languages, "OH" means the same in every language, but I really don't even know if that's true. I'll figure it out, I always do.