Members of the national media are disputing President Trump's decision to blame the "alt-left" for engaging in acts of violence, and many say there is no such thing even though the term has been used for months.

Trump said in a Tuesday press conference that "both sides" bear some of the blame for the violence at a white supremacy rally in Charlottesville, Va., and asked why reporters were ignoring reports that the "alt-left ... came charging at the ... alt-right."

Afterward, some journalists and news organizations delved into his use of "alt-left" as though he had coined it on the spot.

"Trump spoke of the 'alt-left.' Is that a thing?" said a USA Today headline.

A New York Times article described the term as "part of a broad lexicon of far-right terminology," and cited researchers who "say there is no such thing as the ‘alt-left.'"

CNN's headline asked, "What's the 'alt-left'?" Then followed it with, "Experts say it's a 'made-up term.'"

And CBS described the alt-left as "not really a group and more of just an epithet…"

The so-called "alt-right" is a term for a loosely defined nationalist movement. Some of its members embrace white ethnocentrism, including the white supremacist Richard Spencer, who is said to have coined the term.

Neither the "alt-right" nor the "alt-left" originated with Trump but people on both sides use both terms.

The liberal writer James Wolcott wrote a piece for Vanity Fair in March arguing that, "The alt-left can't match [the alt-right] for strength, malignancy, or tentacled reach, but its dude-bros and ‘purity progressives' exert a powerful reality-distortion field online and foster factionalism on the lib-left."

Neera Tanden, president of the Center for American Progress, has accused the alt-left of attacking her.

"I remember last summer when I pointed out Russia's role in leaking/the elections and the alt-left attacked me for McCarthyism," she said in February on Twitter.

Joan Walsh, a liberal writer with the Nation, tweeted in March, "Well, Hillary Clinton made it a brighter place, but that wasn't valued. Even on much of the American left, especially the alt-left."

Some on the left have even embraced the term. The liberal New Republic magazine ran a piece in March declaring "Liberalism Needs the ‘Alt-Left.'"

Trump has, at least on one occasion, distanced himself from the alt-right movement.

During an interview with the New York Times just after the election, he was asked if he thought he animated the group.

"I don't want to energize the group, and I disavow the group," he said. "It's not a group I want to energize, and if they are energized, I want to look into it and find out why."