Sharyl Attkisson did an great video on origins of FakeNews, what is it, where did it come from, and who is behind it? Is FakeNews real? With examples like Richard Jewel, Sandyhook, UVA Campus Rape, Michael Brown. An organization called First Draft started it, and was sponsored by Media Matters and Obama supporters like Eric Schmidt and got Google News Labs involved in created the narrative in 2015: that you could only trust far left sources on what was fake or real. But the FakeNews backfired on the creators like WaPo, that now run from the term, because it applies too well to them.
Wikipedia is both hit and miss, with a lot more hits than misses. I reference it a lot, because most articles are pretty good, or at least good enough. Most of their lies and bias are lies and bias of omission. (What they say isn't usually wrong, but what they don't say might completely change the context). So they are a pretty good reference. But don't let that lull you into an "Appeal to Authority" or "Appeal to Celebrity" fallacy. Science is skepticism. Wikipedia is hegemony. Wikipedia has millions of articles, across hundreds of thousands of topics -- and each topic is a community (clique) of editors, and herd-think rules most of them. Some areas a fine. But if one clique is bad, that whole area can be bad; they won't allow counter-factual that disagree with their agenda. And there are bad (biased) areas of wikipedia. Especially in History, Science, Politics, and anything that's controversial. And everything can be political and controversial to folks that focus on any topic.
While the term goes back 100 years, the history is summed up well in a Sharyl Attkisson TedTalk on FakeNews. While our media has always had false narratives and bad stories that are Fake News (exampled include: Edward R. Murrow's "See it now" McCarthy'ing Joe McCarthy (1954), Richard Jewel story (1996), story about a plane crashing into Camp David after 9/11 (2001), Duke LeCross Rape Case (2014), Michael Brown and 'hands up, don't shoot' narrative (2014), and so on). We didn't use the term "Fake News", just liberal media bias or incompetence, but it's been around since the first liberal got sloppy or partisan at a newspaper, somewhere back in Roman times.
Then on September 13, 2016 Hillary Clinton supporters Google and Eric Schmidt, used a shell charity (a non-profit called "First Draft,") to start seeding the term to attack right wing websites ("to tackle malicious hoaxes and fake news reports"). Hillary Clinton and her surrogate David Brock of Media Matters admitted in a campaign letter that they pressured Facebook to join the effort. Google warned Conservative websites to remove stories that Google didn't like, or they'd take away their ad revenue. And Barack Obama and the liberal media followed along, regurgitating what they were told: none were going to let this opportunity (to curate what information we could see) go to waste, all in the name of protecting free speech. All coincidentally done at the same time, in what could only be a coordinated campaign attack.
Unfortunately for them, it backfired when people noticed that the mainstream liberal media made more errors and was less honest, and started throwing it back in their face. Fake News applied more to the News, Google, Facebook, Obama and other curators and finger pointers than their victims. Donald Trump used that to hijack the term and use it back against them. The left tried to change the narrative and pretend that Trump had created the term, and they wanted to stop using it and claimed it was a hateful term and an attack on free press to point out the Presses bias or errors. And that's where we are today.