Crash? A crash is when it's raining brokers. When entire classes of ordinary investors are wiped out. When the country and the world are headed for bank failures, 12 years of depression and 33 percent unemployment. It is fun to call what's happened since Oct. 19 a crash, but not terribly accurate. The Dow stands today 100 points higher than it did a year ago. A 4 percent gain is not a great return on investment. But it is hardly the apocalypse.

True, a speculative bubble of very recent vintage burst. But the economy shows no sign of crashing. And even the market is now at levels that only a year ago were considered astronomical. Crash? If '29 was Pompeii, which buried everyone and everything, '87 is a mudslide in Malibu. Some MBAs will be buried in their BMWs. The economy may lose a point or two of growth this quarter and next. There will be a minuscule tax increase. Christmas spending will decline, as will consumer confidence. Some crash.

Interestingly, the use of the word in the absence of any cataclysm in the real economy has a kind of cheery, self-celebratory, I-survived-the-crash-of-'87 air to it. Crashes are, after all, exciting. Settled, prosperous, successful bourgeois societies at peace have many things to recommend them. Excitement is not one of them. Now, with outer space temporarily shut down as a theater for the wondrous, the need for drama has had to be satisfied elsewhere, in the self-dramatizing exaggeration of bad news.

Take war. Americans don't particularly like war and have not had the occasion to engage in one for more than a decade. With football (and its blitz, bomb, sack and aerial attack) becoming a less and less satisfying substitute, the vicarious pleasures of combat have had to be sought elsewhere. In fantasy, for example. During the debate on the Persian Gulf, it was argued, correctly, that American sailors are in a situation of possible danger. But that was not quite enough for some congressmen. Last month one Democrat took to the floor of the House to declare, "Today we are at war in all but name." If so, then we need a new word for what happened at Guadalcanal.

The medical world is another fruitful source of drama. Today, of course, the subject is AIDS, which, says the secretary of health and human services, can make the Black Death "look very pale in comparison." To compare a disease as hard to transmit and easy to prevent as AIDS to an indiscriminate killer that in three years left a third of Europe's population dead is political malpractice. But it captures perfectly the hyperbole surrounding AIDS.

AIDS, at least, is a deadly disease. Before AIDS our hankering for hysteria had to make do with far less satisfactory afflictions. Remember the herpes panic? It spawned fear, suspicion, lawsuits and support groups to handle the psychological devastation of a disease whose consequences are, to exaggerate, mild.

It now appears that our government, too, is in crisis. The collapse, disarray, paralysis (choose one) of the Reagan administration was much bruited about during Ginsburg week. Yet as fiascoes go, Ginsburg rates as one of the American presidency's more minor embarrassments and, as Reagan blunders go, is of far less import than Bitburg, let alone Beirut.

Moreover, the relevant feature of Reagan's twilight year is not collapse but compromise -- compromise forced upon a president who lost his political clout in last year's Senate elections and his moral authority shortly thereafter in the Iran-contra affair. Reagan can no longer roll over his opponents. He is being forced to compromise: on taxes, on judges, on contras, even on SDI. But a president forced to deal rather than rule is a return to post-Watergate normality. It is mere melodrama to call it collapse.

Our apocalypses follow so hard on each other that it is difficult to keep track. Just five or six years ago, at the height of the nuclear hysteria, you could not escape the idea that tomorrow was going to be The Day After. This followed the depletion-of-resources doomsday scenario spurred by the oil shocks. In 1973 the Club of Rome offered the much parroted prediction that the world would run out of gold, tin, mercury and silver by now, and that five years hence oil, too, would be a memory. Before that, in 1968 to be exact, Paul Ehrlich's "The Population Bomb" predicted that lack of adequate family planning would cause worldwide famine, pestilence and nuclear war by 1983. It was a best seller. Now we are warned that a birth dearth will do us in.

Crash, war, Black Death, presidential collapse, too many and too few babies. What a sea of troubles. Yet what gives the doomsday game away is the breezy, self-congratulatory tone in which it is offered: By God, the ozone hole -- another crisis to be survived! Last week a visitor from Chile expressed fascination with the enormous popularity of the movie "Fatal Attraction." Where my friend comes from, a midnight knock on the door means secret police, not a discarded lover. To live in a place where the national nightmare is the revenge of the one-night stand is an idea he found rather appealing.