The term dates to the late 1980s when it referred to propagandistic video and audio "news releases" generally created by or for corporate interests. That usage continued through to mid-to-late 2000s decade.

It was applied to more general misinformation in the 2010s, before being 'undefined' by many of the promotors and beneficiaries of fake news.

https://www.sourcewatch.org/index.php?title=Fake_news

https://www.prwatch.org/fakenews/execsummary/

https://www.prwatch.org/fakenews2/execsummary