Wikipedia
The alt-right is a segment of right-wing ideologies presented as an alternative to mainstream conservatism in the politics of the United States. The alt-right has been described as a movement unified by support for Republican Presidential candidate Donald Trump, as well as opposition to multiculturalism and immigration.
The alt-right has no official ideology, but various sources have associated it with white nationalism, white supremacism, antisemitism, right-wing populism, nativism, and the neoreactionary movement.
The alt-right has been said to be a largely online movement with internet memes widely used to advance or express its beliefs, often on websites such as 4chan; much of the coverage of the alt-right has focused on the memes it has produced.