This paper shows why defining „fake news“ is worthwhile and what a suitable definition of “fake news” might look like. We begin by introducing our definition of “fake news” (§2) and employ it to set fake news apart from related phenomena that are often conflated with it (§3). We then extract seven potential dimensions of the concept of fake news from the literature (§4) and compare the most representative definitions that have been proposed so far along those dimensions (§5). In particular, we discuss the definitions by Rini, Gelfert, Dentith, Mukerji, and Zimmermann & Kohring, show up their merits and debits and put them in relation to ours. Although we take our definition as the starting point and argue for it on the side-lines, our primary aims are (i) to enable a systematic evaluation of prevalent definitions with respect to their extensional scope, practical utility, and conceptual transparency, (ii) to demonstrate that there is more widespread agreement than one would think on the outset, and (iii) to show (in §6) that defining “fake news” is not only far from futile, but of vital importance to confront the epistemic threats posed by fake news.