The dictionaries are no help. Both my Webster's New World and the online edition of The Oxford English Dictionary define apocalypse as a "revelation," or specifically, the Revelation of St. John, hewing closely to the Greek meaning of apokaluyiV, "an uncovering, a disclosure." My New Shorter Oxford makes a bow to common usage and says that apocalypse may refer not only to a description of the events of the end of the world, but to "the events themselves"; however, no supporting citations are given.

No matter. At least since Coppola, apocalypse has been used commonly in reference to the destruction of the world; Buffy is no exception. Notably, Riley, in "A New Man," says, "I suddenly find myself needing to know the plural of 'apocalypse.' " While cataclysm, extinction-level event, or the theological eschaton (from the Greek escaton, meaning "the last") might be more pleasing to the ears of prescriptive logophiles, apocalypse is the signifier Joss attaches to the concept of "The End of the World."

But exactly what does the signifier signify?

Buffy: This is how many apocalypses for us now?
Giles: Oh, uh, well . . . (sits, takes off his glasses) six, at least. (sits back slowly) Feels like a hundred.
--"The Gift."

FOR YOUR CONSIDERATION
The Six Apocalypses of "The Gift." Help me here people... For sures, I think: "Prophecy Girl," "Becoming, Part Two," "The Zeppo," "Graduation Day, Part Two." Possibles: "Doomed," "Primeval," "The Gift." Is there any canon on the Six Major Apocalypses faced by Professor Utonium and His Fluffy Battle Kittens?
--Jengod, in BuffyNewsWire, no. 247.

Giles sells Buffy and himself a little short. The events of five episodes are referred to by members of the Scooby Gang as apocalyptic: "The Harvest," "Prophecy Girl," "The Zeppo," "Doomed" and "The Gift." Reference is made to armageddon in "Surprise"/"Innocence" and to destroying the world in "Becoming," totaling seven apocalypses averted by Buffy, et al. I could find no such reference made with respect to the plans of either the Mayor or Adam, though both intended to, if not end the world, at least drastically shrink our comfort zone in it.¹

A word should be said here concerning the difference between the Buffyverse apocalypse and the Christian eschaton, which is, as Riley might have guessed, eschaton has no plural; there will be, according to those who believe there will be one, only one, and it is inevitable. In the Buffyverse, on the other hand, evading apocalypses is a major component of one's time. As Holland Manners says in "Reprise," "Yes, the apocalypse, of course. - Another one of those. Well, it's true. We do have one scheduled. And I imagine if you were to prevent it you would save a great many people. Well, you should do that then. Absolutely. I wasn't thinking--of course all those people you save from that apocalypse would then have the next one to look forward to, but, hey, it's always something, isn't it?"

A word also should be said about the metaphorical dimension of Buffyverse apocalypses, which otherwise will go undiscussed in this essay, but is made explicit as early as "The Harvest." Joyce says, "I know. If you don't go out it'll be the end of the world." While for Christian millenarians existence will have just one ending, the world of a teenager has many cataclysms. This may be why I'm so strongly tempted to include "Graduation Day" in my list of apocalyptic events, and why I have included "Surprise"/"Innocence," despite its differences from the others. These are the episodes (along with "Prophecy Girl," "Becoming," and "The Gift") where Buffy's (and our) comfortable conception of her world can be said to have ended, to be replaced with something less comfortable, even if the material world was not destroyed. The prosaic nature of material apocalypses is highlighted by the inclusion of "The Zeppo," where apocalypse is merely a sideshow, and "Doomed," where apocalypse is a letdown after the artistic high point of "Hush," on my list. The world might end, but it's nothing to get excited about.

The apocalypses on my list share certain material characteristics. Four of them ("The Harvest," "Prophecy Girl," "The Zeppo" and "Doomed") involve opening the Hellmouth, and two others ("Becoming" and "The Gift") involve otherwise breaking down the distinction between our world and that of the demons. Stephen Jay Gould, in his essay "The Narthex of San Marco and the Pangenetic Paradigm,"² writes that Genesis 1 might better be interpreted as not a record of addition, but of differentiation, between light and dark, day and night on the first day, between the waters above the firmament and the waters below on the second, between land and sea on the third, between undifferentiated chaos and order. Indeed, dichotomization is the basis for much of our definition of our existence. To eliminate the ability to define a clear boundary between our world and the demon dimensions is to cripple our ability to understand our world. These apocalypses then are cataclysms in the same sense that the cataclysms of Deucalion and Noah destroyed our ability to distinguish between the waters above the firmament and below and returned us to chaos. They mean the end of the world, not only as we know it, but as we know it. (Plus, as Giles mentions in "Becoming, Part One," we'd suffer "horrible and eternal torment.")

The Judge in "Surprise"/"Innocence" and what Doyle saves us from in "Heroes," present a different form of apocalypse. More "extinction-level events" than cataclysms, we are faced not with the destruction of the world or of our ability to understand the world, just our own extinction and the reclamation of this world by the demons. I must confess that of all the apocalypses faced by Buffy and crew, the Judge affected me the most. There's something about being targeted for what makes us essentially human that scares the bejeezus out of me. And while the beacon of the Scourge (which destroyed anything with human blood and thus would have killed Angelus) beats the Judge (who destroyed anything with humanity and thus spared him) on points, the shift in targets from the material blood to the metaphysical humanity is a shift from what we are made of to what we are.

One question remains: which of the apocalypses required Buffy for their prevention? It is not clear that the presence of the Slayer is a necessity for the survival of humanity in all of these cases. While only Buffy certainly could have closed Acathla, Glory's portal, and perhaps the Hellmouth, the Judge and the Mayor (despite my mentioning the Mayor here, "Graduation Day" is still not, in my opinion, an apocalypse) could have been contained without her. Though rocket launchers and a ton of explosives are "thinking outside the box" for the Slayer, they tend to come quickly to the mind of the National Guard. Also, we have seen the early stages of the Hellmouth being opened, but never the final result. Would the Hellmouth's opening really constitute an apocalypse?

Other than Dawn's very existence, the strongest counterfactual³ we have seen on Buffy is "The Wish," in which the events of "The Harvest" have apparently transpired without Buffy there to stop them. The Master has escaped his bonds, as he intended in "The Harvest," but if he has opened the Hellmouth, it has had little effect. The library is intact, making it doubtful that he has. Vampires boldly walk the street, but the sort of demons we have come to expect from episodes like "Graduation Day, Part Two" are nowhere to be seen. And, unless the high level of demonic activity in Cleveland is the result of the Master's release (and I suspect it is instead the legacy of Art Modell), the effects seem localized. Sunnydale has undergone a cataclysm, but the world is intact.

The idea that Buffy in some way creates the problems that she then solves has often been discussed here, most memorably producing OnM's Kwisatz Haderach theory. Indeed, she often is, if not essential to the prevention of an apocalypse, essential to the instigation of an apocalypse. In "Prophecy Girl," the Master tells her that if she hadn't come to stop him, he would not have been released. Without her, Angelus would never have had the inclination to wake Acathla. And while she has a perfect record in preventing the apocalypses she faces, she seems to be in some way contributory to at least half of them.

Not that I'd hold it against her.

All episode quotes taken from Psyche Buffy Transcripts.