Who put the bump in the bump-da-bump-da-bump? Who knows? It must have happened in some obscure corner of the political universe when no one was looking: The Big Mo died and the Iowa Bump and its twin, the Iowa Bounce, were born.

"My sense is there is no comparison to the bump Gephardt gets out of this compared to what Gary Hart got in 1984," opined New Hampshire state Democratic Party Chairman Joseph Grandmaison after Gephardt's win in Iowa.

"Gephardt will certainly get a bounce," countered Keating Holland, survey manager for CBS.

"If Gephardt doesn't get that bounce out of the Iowa coverage, he's going to have a tougher time competing in Super Tuesday," speculated University of California at Berkeley political science Professor Nelson W. Polsby.

Say hello to the metaphors of the week, the latest entries in the lexicon of political jargon.

"I only started hearing it this year," says David Yepsen, political writer for The Des Moines Register. "We were all talking about it four years ago, but the name is new."

This is, after all, the profession where discussions are studded with gems like "the expectation gap" and "low-balling," "an uptick in the polls," "spin kings" and "spin patrols," "a saturation buy in the fourth-largest ADI" and "Bush is doing 1,300 points." (For the uninitiated, the last two have to do with the ratings for campaign commercials.)

"There's a very good reason for wanting to think about the effect of the Iowa caucuses on the future fortunes of candidates," says Polsby. "That's because we have historical experience that the Iowa caucuses have been important, especially after the mass media finishes interpreting them."

And what would be the fun of thinking about such things if every thought didn't get a label both easy to remember and suggestive that whoever uses it resides in the world of the insiders, where every describable event can be transformed into an acronym, phrase or figure? "Communicating your importance by speaking in idiom" is how longtime political consultant Thomas Donilon describes it.

Not everyone, however, seems to have heard about the shift in jargon. On Wednesday, Dole slipped back a few years when he told an audience, "I see some momentum out there," and earlier Ray Wieczorek, Republican chairman of Manchester, N.H., told one reporter, "If you don't get the momentum out of New Hampshire you can be a really hurting dude in the South."

Where have these guys been?

Other cliche' sightings include Pat Robertson's much-discussed "invisible army." "I've also heard it referred to as the army of the night," says Donilon. And then there is the ever-popular "leadership," an amorphously defined attribute somehow akin to that elusive subject that Bush -- who made history by dragging the Big Mo out of football idiom and applying it to politics -- calls "the vision thing."

Of course, a desire to create a political cliche' can return to haunt you, as it did for Bush when he appropriated the Big Mo.

"All I hear about is momentum," Dole said in 1980 after Iowa. "I hear talk about 'Little Mo' and 'Big Mo' and I don't know who's who."

And now, as Bush's campaign attempts to pull itself together following his Iowa third-place finish, all too many self-appointed pundits are tempted to coin -- again and again -- the inevitable "Slo Mo" and "No Mo."

But back to the Bounce.

"I'll give you Polsby's Fourth Law," says Polsby himself, when asked where he picked up the phrase. "Famous sayings migrate into famous mouths, so almost certainly it will be attributed to someone famous. Dorothy Parker and Winston Churchill are always the two main candidates."

Some reporters avoid the whole problem of derivation and write something like "what professionals call the Iowa 'bounce.' " Grandmaison says he thinks Washington Post columnist David Broder coined the Bump and Bounce, but Broder says he can't remember.

"Who's ever going to know?" Yepsen says about the source of the Bounce. "That's one of the great things about taking credit for idioms -- accountability is very low."

Let us turn, then, to an expert: Beth Simon, an editor of the Dictionary of American Regional English in Madison, Wis.

"Hmmm, let's see," she says as she flips through her pages. "There are a couple of meanings for 'bounce' as a verb. To make an animal start from cover, to make an animal change direction -- which isn't really getting there, but it is a movement. Generally, to give someone the bounce is to dismiss them. You can easily see how they've made it. Bump is probably from bumper car, and bounce seems very clearly from some trampoline effect."

But the phrases will receive no entries in the dictionary, which is still in production.

"They may be so much political jargon that we've not taken it for that reason," says Simon. "We do take certain kinds of jargon, but it has to do with things like mining, something that's affected the United States."

Which raises some intriguing questions about the primary process that are probably better left unexplored.