'Y2K pop revival' refers to the 2020s nostalgia-driven resurgence of late-1990s and early-2000s pop music aesthetics — Britney, Christina, NSYNC, Destiny's Child, low-rise jeans, butterfly clips, bedazzled accessories. Driven by Gen Z's discovery of an era they were too young to live through. If your teen is into Y2K pop revival, they are engaging with a major cultural trend. Wholesome retro fun.