You guys, just look at this thing.
This title just piles contradiction on top of contradiction! How? Let us count the ways.
First of all, we've got the paradox that Dickens claims that the story is a "Christmas Carol" but one that is "in prose." Now, a carol is what we think it is—a song with metered and rhyming lyrics that is delivered live and out loud, usually on just one night of the year. That's why the chapters in this thing are called "staves"—that's another word for verses.
And prose? Well, prose is pretty much the exact opposite of that. It's written, unmetered and unrhymed, and usually meant to be read rather than listened to (and probably, Dickens hopes, read over and over again rather than just the one time).
And on the other side of the colon, we've got another bit of weirdness: it's a "story of Christmas" that is actually a "ghost story."
Well, Charlie—which is it? Okay, stories about Christmas are usually stories about, you know, the whole no-room-at-the-inn-baby-Jesus-in-the-manger thing. Or else at least something to do with Christianity and the religious underpinnings of the holiday. They definitely don't usually include ghosts, which are strictly for Halloween.
So why all this mixing and matching? Why have a title that muddles and confuses readers about what they are about to read? What would be different if this were simply titled "Ebenezer Scrooge"? Would the story then be as universal as it seems now, or would readers be too fixated on just this one guy to get the larger message about the whole season?
Here's a theory. For one thing, this title plays up the more surprising elements of the story. Sure, nowadays the story of Scrooge is as entrenched in the Christmas tradition as trees, Santa, and even the Grinch. But back then, ghosts and curmudgeons were not exactly rolling in on the Yuletide. Dickens is telling us, right off the bat, that this ain't your mama's Christmas story. It's something entirely new.