Is America heading down the rabbit hole where words have lost meaning? (Go ask Alice.) (Chip Somodevilla/Bloomberg)

We have officially crossed through the looking glass on the subject of trust in the traditional news media.

Yes, we’re in a land described in the Lewis Carroll classic where meaning is exceedingly hard to pin down.

“When I use a word,” Humpty Dumpty said in a rather scornful tone, “it means just what I choose it to mean — neither more nor less.”

“The question is,” said Alice, “whether you can make words mean so many different things.”

“The question is,” said Humpty Dumpty, “which is to be master — that’s all.”

A new Monmouth University poll says that 3 of 4 Americans believe that traditional news organizations report “fake news.”

I’ve been arguing for more than a year that the term should be shunned because its original meaning — that is, fabricated stories intended to fool you — has been so purposely blurred and tainted.

That’s largely the doing of President Trump, who wants nothing more than to have the American public distrust the reality-based press that often reports unflattering — but true — things about him.

Just Tuesday he was tweeting about the “Fake News Networks, those that knowingly have a sick and biased AGENDA.”

The poll set out to measure American beliefs about “fake news,” without clarity about its kaleidoscopic meanings.

Are we talking about factual journalism that a politician doesn’t like (for example, The Washington Post’s reporting on the sexual misconduct of former Alabama judge Roy Moore, which his wife labeled “fake news”)? Or about flat-out lies such as “the pope has endorsed Donald Trump” that circulated on social media during the presidential campaign?

The poll never manages — or really tries — to differentiate between those meanings, or a bunch of others.

Naturally, pro-Trump media outlets made hay with it, none more so than Breitbart News, which splashed a clumsy photo illustration of a trash fire labeled CNN, accompanied by a huge headline: “77 percent believe traditional media guilty of fake news.”

It sure sounded bad, even though the 800 respondents, by a 48 to 35 percent margin, did allow that they trust CNN more than the president.

Chris Cillizza of CNN tweeted a cry of frustration: “ARGHHHHHHHHHH.”

Dig down a layer, though, into the poll’s substance and, while you’ll find cause for legitimate alarm, you’ll also find a troubling conflation of terms.

Consider Question 39a, which asks whether traditional major news sources like TV and newspapers report fake news stories “on purpose in order to push an agenda or do they tend to report them more by accident or because of poor fact checking?”

“When you see the result, you don’t know what it means,” argued Tom Rosenstiel, executive director of American Press Institute, who has a background in polling with Pew Research.

“It could mean stories I don’t like, stories that are critical of a person I like, stories that have a factual error, stories that are fundamentally wrong, or stories made up out of whole cloth by pranksters or political propagandists,” he said.

Patrick Murray, director of Monmouth’s polling institute, said that conflation doesn’t worry him.

The poll’s aim, he said, was not to tease out what people mean when they use the term but to measure their overall views.

“The term has become amorphous, but conceptually, it means a lot of people think the media can’t be trusted.”

And, he added, “there’s no question that Donald Trump has been very successful at framing how people see the media. He has undermined trust.”

Now that “fake news” can mean almost anything, it has come to mean almost nothing.

In that way, it’s become about as useful as the term “the media” — so general as to be pointless. (Are we talking about Fox News, your Facebook feed, NPR, the Chicago Tribune, or some unholy combination of everything you see on a screen, read on a printed page or hear on the airwaves?)

Given that confusion, it’s no surprise that many people say they don’t trust the media.

And if “fake news” includes “factual coverage that I don’t like,” it’s no wonder the negative numbers are so high. If it also includes “editorial decisions” that reflect negatively on a particular officeholder, it’s even less wonder.

It’s tempting to say, then, that this poll’s findings are just as meaningless as the term itself. It’s tempting to dismiss the findings as mortally flawed.

But the Humpty Dumpty effect is worrisome. When words can mean anything, and a truth-averse president has made himself the master of meaning, democracy is in peril.

For more by Margaret Sullivan visit wapo.st/sullivan