Definition of "twenteen"

The classic banner ad that had been driving Internet marketing for a decade would eventually die off, because on social networks it wasn't about throwing ads like confetti at users—it was about integrating product experience. And the demographic that first tuned into social networks—teens, “twenteens,” which was how some in their early twenties not ready to graduate to adulthood referred to themselves, and young working stiffs—were the consumers of the future.

2010, Adam Penenberg, Viral Loop: The Power of Pass-It-On

But something new was rippling through a million MySpace profiles. The sound was electro, and bass-laced synthetic dance pop would soon start streaming in from producers in Paris, dizzying the twenteens of Britain with its accessible, anthemic funk.

2015, Rose Bretécher, Pure