what the term "virtual particles" referred to I wanted to know what the term "virtual particles" referred to. I found many "descriptions" of them on webpages. Fine. Then I went to the index of many advanced QM books, and the term "virtual" doesn't really show up as prominently as I thought it would. Is virtual "slang"? If so, what is the proper term for a virtual object so that I may focus on those pages that describe them?