The alt-right, shorthand for “alternative right,” is the blanket term for a loose gathering of conservatives primarily based online that can include everyone from critics of so-called “political correctness” on college campuses to hardcore white supremacists and neo-Nazis.

Here are 5 things to know about the group:

1. Until recently, the 'alt-right' was largely removed from partisan politics

That all changed this year as the movement rose from obscurity thanks to its followers’ intense support for Donald Trump’s candidacy, the rise of conservative outlets like Breitbart that explicitly champion “alt right” causes, and the rapid spread of “alt-right” users on sites like 4chan, Reddit, and Twitter. Steve Bannon, the president of Breitbart, recently took over as Trump’s campaign CEO, drawing more attention to Trump's ties to the movement.

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What unites these disparate groups together in the broadest sense is a shared belief that mainstream politics, culture, and media are suppressing their views on topics like race, gender, immigration, foreign policy, and religion. Some are “men’s rights activists” who blame feminism for weakening the country, others are conservative foreign policy dissidents who reject America’s alliance with Israel or favor more isolationist policies. They tend to be younger and more online-savvy than mainstream conservatives, often communicating with memes and obscure internet jokes. The “Pepe The Frog” cartoon has become an especially popular symbol for Trump.

2. It's linked to the "White Nationalist" movement

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The term is derived from “AlternativeRight.com,” a onetime web publication published by Richard Spencer, who, like a number of figures associated with the "alt-right," belongs to the "white nationalist" movement. White nationalists argue that white Americans must form a united interest group that rejects multiculturalism and blocks immigration in order to keep the country more racially homogenous.

Some “Alt-right” defenders argue there are important distinctions between white identity politics and old-fashioned racism, but organizations dedicated to tracking extremist groups view the movement as their latest iteration. The Southern Poverty Law Center and Anti-Defamation League have both issued reports warning about the rise of alt-right, which the latter terms “the new white supremacy.”

3. A central figure in popularizing the “alt-right” is a Breitbart writer

More recently, writer Milo Yiannopoulos, a conservative provocateur recently banned from Twitter for organizing a harassment campaign against Ghostbusters star Leslie Jones (the all-female Ghostbuster remake has been a major target in the “alt-right”), has been central to the movement. Yiannopoulos is also an honorary moderator at r/The_Donald, a pro-Trump subreddit with millions of monthly users that’s become popular with the “alt-right.” Trump visited the site for a Q&A shortly after accepting the Republican nomination.

Related: Trump's Reddit Fan Club Faces Crackdown, Infighting

Yiannopoulos is highly associated with “Gamergate” a related movement to the “alt-right” that consists of mostly young male video game fans who warn that so-called “social justice warriors” are conspiring to produce games more targeted to female and minority customers. “Gamergaters” became notorious for their own harassment efforts—two regular targets, feminist essayist Anita Sarkeesian and game designer Zoe Quinn, ended up addressing the United Nations to highlight cyberbullying.

4. Trump has not officially embraced the “alt-right” by name

However, Trump has regularly retweeted fringe users with names like “WhiteGenocideTM” and sometimes passed on images associated with extremist supporters.

During the primaries, he retweeted phony crime statistics that originated in white supremacist circles accusing black criminals of targeting whites. Pressed by Fox News’ Bill O’Reilly about the blatantly racist image, Trump defended it as coming from a credible source. More recently Trump’s Twitter account tweeted an image of Hillary Clinton along with a Jewish star and a pile of money that reportedly came from an extremist user. Trump again defended the tweet, saying it was misinterpreted.

The “alt-right” movement has come under particular criticism over online campaigns against its enemies that many blame its followers for encouraging. In particular, Jewish journalists like magazine writer Julia Ioffe, New York Times reporter Jonathan Weisman, and former Breitbart writer Ben Shapiro have been inundated with memes on social media referencing the Holocaust, anti-Israel extremism, and Nazi-era propaganda.

Related: How an Army of Pro-Donald Trump Trolls Are Taking Over Reddit

Trump’s reaction to the attacks on Ioffe, who wrote a profile of his wife Melania Trump for GQ, was instructive. After CNN’s Wolf Blitzer brought them up on air, he pointedly refused to condemn them.

“I don’t have a message to the fans,” Trump said. “A woman wrote an article that’s inaccurate.”

5. Some Republicans fear the extremism

Trump’s popularity with the “alt-right” and the movement’s ongoing efforts to target his conservative critics has alarmed some Republicans, who fear that the party could become infected with extremism. Speaker Paul Ryan notably called it out while facing a primary challenge from Paul Nehlen, a fringe candidate who floated a proposal to deport all Muslims in America during the race. Nehlen drew national support in “alt-right” circles, including on Breitbart.