Abstract: “Fake news” was chosen in 2017 as the word of the year by the Collins Dictionary and the American Dialect Society, due to its extraordinary popularity. However, its relevance has been called into question due to its controversy and ambiguity. We have compiled herein 30 definitions from selected dictionaries, academic papers, news agencies, influential media observatories, and independent, certified fact-checkers over the last six years and have carried out a manual relational content analysis on them. We also collected data from four bibliometric studies from academic literature and five surveys on how the general public perceived fake news. In keeping with this three-level systematic review (lexicography, bibliometrics, and public perception) we detected some trends, including a growing drift towards a post-truth-driven conceptualization of fake news. Results also show that the “viral” and “memetic” quality of a rumor prevail over the demonstrable credibility of a source and even the factuality of a reported event; the element of surprise or outrage in the heat of the moment is more powerful than the ironic detachment elicited by news satire and parody; and sharing motivations are definitely less concerned with perceived accuracy than with partisan support, community sentiment, emotional contagion, and a taste for the sensational or bizarre.