I can recall -- and it doesn't seem that long ago, really -- when the "b" word -- billion -- was still something of a novelty in Washington. I was working there in those days and even we Washingtonians had to have it explained to us: a billion is a thousand million dollars, which was one way of helping get our minds around it. Carl Sagan used the word in his PBS "Cosmos" series, sometimes ad nauseum, to illustrate the incomprehensible vastness of space. But it was still a very big number even by Washington standards.
I think I can also recall when annual budget deficits, which had been counted in hundreds of millions of dollars, began being counted in billions of dollars, and then billions and billions of dollars, as Sagan would say. Trillion (which I think is a thousand billion dollars) was still a word rarely used. It began being applied to the national debt at some point -- which is the accumulation of deficits, plus the cost of borrowing money to finance it -- but it was never imagined that it would one day be applied to the deficit. And that just wasn't that long ago.
What comes after a trillion? Maybe a zillion? Or a bazillion? I guess I'll have to Google it and find out. Whether I want to accept it or not, it's probably a number that's in our fiscal future.