issei me-ru, "together-mail".
This word appeard on a title from today's newspaper. It never came to my knowledge before, however it is easy to understand: an e-mail being sent to multi receivers at the same time. It took me some time to find out its English equivalence, with a help, I came to the word "mass email". On the other hand, it is obvious that the newpaper artical writer does not believe that this word may be fully understood by all readers, thus in the article, this was carefully expressed in a longer statement, "一斉にメールを...".
We need new words to describe new phenomena. Keep that in mind, it is not hard to find many interesting examples, and this word is one of them.