Fox News Channel's Sean Hannity speaks during a campaign rally for Republican presidential candidate Ted Cruz (R-Tex.) in Phoenix in March. (Rick Scuteri/AP)

On Wednesday, the conservative-leaning advocacy group One Nation released a statement on Elizabeth Warren and Bernie Sanders.

“Elizabeth Warren and Bernie Sanders Lead Alt-Left in Hijacking of Bipartisan Medical Research Bill,” the subject line read.

Wait. “Alt-left?”

You may have heard of the alt-right — especially in recent weeks as former Breitbart News head Stephen Bannon has been given a top role in shaping President-elect Donald Trump's administration and agenda. There remains plenty of disagreement about what exactly “alt-right” means, but it's a loaded political term carrying connotations of white nationalism and even racism. And thusly, Democrats are gleefully attaching the term to the Trump administration and the Trump-led Republican Party.

The GOP's response: I know you are but what am I. Yep, apparently they're going to start calling what they view as more extreme Democrats the “alt-left.”

The term isn't brand new, but it has just now gradually worked its way into the mainstream. It started with alt-right websites like World Net Daily and has graduated to the airwaves of Fox News and Sean Hannity, who has been using it for a couple of weeks now. And Trump, who has distanced himself from the alt-right term, may have played a major role in pushing it into the conservative lexicon.

“Nobody even knows what [alt-right] is,” Trump told CNN's Anderson Cooper in August when asked about Bannon's comments tying Breitbart to the alt-right. “This is a term that was just given that — frankly, there's no alt-right or alt-left. All I'm embracing is common sense.”

Previously, the term had appeared intermittently on sites like WND and CNS News and even in a syndicated column in Canadian newspapers hitting the media's coverage of Trump. But Trump's mention seemed to bring it to the attention of more mainstream conservatives.

The same night Trump used it, Lou Dobbs dropped a reference on his Fox Business Network show. A couple days later, the Washington Times' Kerry Riddell appeared on Fox News's “Media Buzz” and took issue with the media trying to label Trump's supporters as bigoted and racist: “If they're going to do that, do it with her or do it with her alt-left supporters.”

By Sept. 11, conservative activist Gary Bauer used the term on Jake Tapper's CNN show. “It's not alt-right, it's not alt-left; it's alt-delete. It's get the bums out,” he said of the election. Dobbs said it again on Oct. 4.

After Trump won the election, Anthony Scaramucci, a member of his transition team, dropped the term again on Hannity's show  Nov. 14. “And so what's interesting about the alt-left — just to add this to it — they're not focused on [the forgotten people]. They think these people are misogynists and misanthropes and negative people.”

At the end of the same show, Hannity used the “alt-left” in his question of the day: “Since the mainstream liberal, alt-left media, radical media, their coverage was so biased against President-elect Trump, do you think they owe him an apology?”

Since then, it has been a mainstay. A week later, Hannity and BuzzFeed's Rosie Gray debated whether there is an “alt-radical left.”

The Hannity-Gray debate is well worth a watch, and it crystallizes why conservatives like Hannity have seized upon “alt-left.” The host basically seems to take exception to the idea that there exists racism and bigotry in the conservative movement and feels the “alt-right” label is being unfairly tied to the whole GOP, suggesting the entire party is extreme.

The use of the term “alt-left,” then, would seem to be a way to point out that there are also extremists on the left — a fact that these conservatives believe is being ignored.

That's undoubtedly true; these things are a matter of degree, after all. But the difference between alt-right and alt-left is that one of them was coined by the people who comprise the movement and whose movement is clearly ascendant; the other was coined by its opponents and doesn't actually have any subscribers.

“Alt-right” was a term first used by white nationalist Richard Spencer, who recently appeared at a Washington alt-right gathering and yelled “Hail Trump! Hail our people! Hail victory!” while some in the crowd made Nazi salutes. The alt-right has long used the term to identify itself. And Bannon himself previously embraced the term, saying this summer that Breitbart served as a “platform for the alt-right.”

He reportedly doesn't like the term anymore, and Republicans including Trump are shunning it these days. But Bannon's “platform” comment, the demonstrated alt-right flavor of Breitbart's journalism and Trump's reliance on such alt-right-friendly and conspiracy theory-oriented media outlets have given this movement a voice it didn't have before.

You can make an argument that the alt-right is being over-applied, but at least it's a thing. And it's apparently a pretty potent thing, given conservatives now want to use the inverse as a political attack.