If you can define something by giving an example, this story from the Washington Post just might serve as your quintessential definition-by-example of irony. In an attempt to convince everyone that "fake news" and the Russians somehow rigged the election in favor of Donald Trump, the Post has served up a story so absurd and unintentionally hilarious, it's almost as if they wrote their own fake news to help us recognize the genre.
It's true. The venerable voice of the establishment actually published this (bolded passages by me):