For most of the last century, “pop music” has been a durable single phrase with two distinct meanings: a statement of fact about the most listened to music of the moment as well as a genre with specific traits. And for a majority of that time, the two definitions have neatly intersected. Pop songs from “I Want to Hold Your Hand” to “Umbrella” have also been the most popular songs of their day.

And especially since the 1980s, pop has been the domain of a particular type of entertainer: a virtuoso performer, visual artist, cultural maven, pop arbiter, and chart baron known as a pop star.

But thanks in part to the pluralizing forces of the Internet, pop—like so many other things—has splintered. In the last two years, the popular-music ecosystem has proven more hospitable to SoundCloud rappers, novelty E.D.M./country hybrids and a freestyle from Cardi B than it’s been to once-indomitable pop stars like Taylor Swift. Meanwhile, former and would-be pop stars like Kesha, Troye Sivan, and Carly Rae Jepsen have grown into artists with devoted cult followings as opposed to global superstars. While there are exceptions—Bruno Mars in particular mimics the established pop-star formula to massive success—something novel is clearly afoot: pop music is no longer the most popular music in 2018.

Pop as a genre is squishy. Since “popular” is in the name, it’s somewhat beholden to trends. There have, however, been some constants: big, broad emotions, a light touch driven by melody, and music and lyrics that are uncomplicated and familiar. Pop nicks elements from other genres—a guitar lick, a rap—but funnels everything through a tried-and-true structure, two verses and a bridge punctuated with an inescapable hook.

More pertinently, pop music is inextricably linked to the pop star, a brand of musical supernova usually associated with 80s titans like Michael Jackson and Madonna. These larger-than-life entertainers defined a well-worn—and perhaps now rundown— version of musical superstardom, trading in a mastery of visual mediums, untouchable virtuosity, and uber-polished live performance, usually incorporating dance. Mostly, though, their all-in take on pure pop music dominated the charts. In their decades-long careers, Jackson accumulated 13 No. 1 singles, Madonna, 12. Their contemporaries—Whitney Houston, Mariah Carey, and Janet Jackson among them—followed that path to similar success.

And for the next four decades, a flood of descendants followed in their tracks. Britney, Beyoncé, Justin Timberlake, Chris Brown, Jennifer Lopez, Rihanna, and Lady Gaga all built on the model set forth by Jackson and Madonna. While the elements were touched up to suit the moment, every successive generation took the same approach and filled the same general groove—and the chart positions—of their predecessors with scientific precision. As such, direct comparisons, for better or worse, were inescapable.

The last few years, however, has seen a huge disruption in this lineage. The idea of “the Flop” has traveled from movie blockbusters to pop albums, particularly those released by pop stars with woefully little impact. Both 2017 and 2018 played host to an utter litany of flops. Katy Perry, Kesha, Lorde, Fergie, Miley Cyrus, Timberlake, and Swift, all of whom recently owned the zeitgeist, have released notably underperforming albums; half of those albums failed to achieve a single top 10 hit. Even Beyoncé, a chronic cultural arbiter and megastar, has not reached the top 5 as a lead artist on the Hot 100 since 2013’s “Drunk in Love.” Her latest, Everything Is Love—a collaboration with her husband, Jay-Z—will be the latest test of her unique stature as a pop-cultural agenda-setter who endures without multi-format hit singles.